Isabelle NEWS -- history of user-relevant changes

 =================================================

 (Note: Isabelle/jEdit shows a tree-view of the NEWS file in Sidekick.)

 New in Isabelle2020 (April 2020)

 --------------------------------

 *** General ***

 * Session ROOT files need to specify explicit 'directories' for import

 of theory files. Directories cannot be shared by different sessions.

 (Recall that import of theories from other sessions works via

 session-qualified theory names, together with suitable 'sessions'

 declarations in the ROOT.)

 * Internal derivations record dependencies on oracles and other theorems

 accurately, including the implicit type-class reasoning wrt. proven

 class relations and type arities. In particular, the formal tagging with

 "Pure.skip_proofs" of results stemming from "instance ... sorry" is now

 propagated properly to theorems depending on such type instances.

 * Command 'sorry' (oracle "Pure.skip_proofs") is more precise about the

 actual proposition that is assumed in the goal and proof context. This

 requires at least Proofterm.proofs = 1 to show up in theorem

 dependencies.

 * Command 'thm_oracles' prints all oracles used in given theorems,

 covering the full graph of transitive dependencies.

 * Command 'thm_deps' prints immediate theorem dependencies of the given

 facts. The former graph visualization has been discontinued, because it

 was hardly usable.

 * Refined treatment of proof terms, including type-class proofs for

 minor object-logics (FOL, FOLP, Sequents).

 * The inference kernel is now confined to one main module: structure

 Thm, without the former circular dependency on structure Axclass.

 * Mixfix annotations may use "' " (single quote followed by space) to

 separate delimiters (as documented in the isar-ref manual), without

 requiring an auxiliary empty block. A literal single quote needs to be

 escaped properly. Minor INCOMPATIBILITY.

 *** Isar ***

 * The proof method combinator (subproofs m) applies the method

 expression m consecutively to each subgoal, constructing individual

 subproofs internally. This impacts the internal construction of proof

 terms: it makes a cascade of let-expressions within the derivation tree

 and may thus improve scalability.

 * Attribute "trace_locales" activates tracing of locale instances during

 roundup. It replaces the diagnostic command 'print_dependencies', which

 has been discontinued.

 *** Isabelle/jEdit Prover IDE ***

 * Prover IDE startup is now much faster, because theory dependencies are

 no longer explored in advance. The overall session structure with its

 declarations of 'directories' is sufficient to locate theory files. Thus

 the "session focus" of option "isabelle jedit -S" has become obsolete

 (likewise for "isabelle vscode_server -S"). Existing option "-R" is both

 sufficient and more convenient to start editing a particular session.

 * Actions isabelle.tooltip (CS+b) and isabelle.message (CS+m) display

 tooltip message popups, corresponding to mouse hovering with/without the

 CONTROL/COMMAND key pressed.

 * The following actions allow to navigate errors within the current

 document snapshot:

   isabelle.first-error (CS+a)

   isabelle.last-error (CS+z)

   isabelle.next-error (CS+n)

   isabelle.prev-error (CS+p)

 * Support more brackets: \<llangle> \<rrangle> (intended for implicit argument syntax).

 * Action isabelle.jconsole (menu item Plugins / Isabelle / Java/VM

 Monitor) applies the jconsole tool on the running Isabelle/jEdit

 process. This allows to monitor resource usage etc.

 * More adequate default font sizes for Linux on HD / UHD displays:

 automatic font scaling is usually absent on Linux, in contrast to

 Windows and macOS.

 * The default value for the jEdit property "view.antiAlias" (menu item

 Utilities / Global Options / Text Area / Anti Aliased smooth text) is

 now "subpixel HRGB", instead of former "standard". Especially on Linux

 this often leads to faster text rendering, but can also cause problems

 with odd color shades. An alternative is to switch back to "standard"

 here, and set the following Java system property:

     isabelle jedit -Dsun.java2d.opengl=true

 This can be made persistent via JEDIT_JAVA_OPTIONS in

 $ISABELLE_HOME_USER/etc/settings. For the "Isabelle2020" desktop

 application there is a corresponding options file in the same directory.

 *** Isabelle/VSCode Prover IDE ***

 * Update of State and Preview panels to use new WebviewPanel API of

 VSCode.

 *** HOL ***

 * Improvements of the 'lift_bnf' command:

   - Add support for quotient types.

   - Generate transfer rules for the lifted map/set/rel/pred constants

     (theorems "<type>.<constant>_transfer_raw").

 * Term_XML.Encode/Decode.term uses compact representation of Const

 "typargs" from the given declaration environment. This also makes more

 sense for translations to lambda-calculi with explicit polymorphism.

 INCOMPATIBILITY, use Term_XML.Encode/Decode.term_raw in special

 applications.

 * ASCII membership syntax concerning big operators for infimum and

 supremum has been discontinued. INCOMPATIBILITY.

 * Removed multiplicativity assumption from class

 "normalization_semidom". Introduced various new intermediate classes

 with the multiplicativity assumption; many theorem statements

 (especially involving GCD/LCM) had to be adapted. This allows for a more

 natural instantiation of the algebraic typeclasses for e.g. Gaussian

 integers. INCOMPATIBILITY.

 * Clear distinction between types for bits (False / True) and Z2 (0 /

 1): theory HOL-Library.Bit has been renamed accordingly.

 INCOMPATIBILITY.

 * Dynamic facts "algebra_split_simps" and "field_split_simps" correspond

 to algebra_simps and field_simps but contain more aggressive rules

 potentially splitting goals; algebra_split_simps roughly replaces

 sign_simps and field_split_simps can be used instead of divide_simps.

 INCOMPATIBILITY.

 * Theory HOL.Complete_Lattices:

 renamed Inf_Sup -> Inf_eq_Sup and Sup_Inf -> Sup_eq_Inf

 * Theory HOL-Library.Monad_Syntax: infix operation "bind" (\<bind>)

 associates to the left now as is customary.

 * Theory HOL-Library.Ramsey: full finite Ramsey's theorem with

 multiple colours and arbitrary exponents.

 * Session HOL-Proofs: build faster thanks to better treatment of proof

 terms in Isabelle/Pure.

 * Session HOL-Word: bitwise NOT-operator has proper prefix syntax. Minor

 INCOMPATIBILITY.

 * Session HOL-Analysis: proof method "metric" implements a decision

 procedure for simple linear statements in metric spaces.

 * Session HOL-Complex_Analysis has been split off from HOL-Analysis.

 *** ML ***

 * Theory construction may be forked internally, the operation

 Theory.join_theory recovers a single result theory. See also the example

 in theory "HOL-ex.Join_Theory".

 * Antiquotation @{oracle_name} inlines a formally checked oracle name.

 * Minimal support for a soft-type system within the Isabelle logical

 framework (module Soft_Type_System).

 * Former Variable.auto_fixes has been replaced by slightly more general

 Proof_Context.augment: it is subject to an optional soft-type system of

 the underlying object-logic. Minor INCOMPATIBILITY.

 * More scalable Export.export using XML.tree to avoid premature string

 allocations, with convenient shortcut XML.blob. Minor INCOMPATIBILITY.

 * Prover IDE support for the underlying Poly/ML compiler (not the basis

 library). Open $ML_SOURCES/ROOT.ML in Isabelle/jEdit to browse the

 implementation with full markup.

 *** System ***

 * Standard rendering for more Isabelle symbols: \<llangle> \<rrangle> \<bbar> \<sqdot>

 * The command-line tool "isabelle scala_project" creates a Gradle

 project configuration for Isabelle/Scala/jEdit, to support Scala IDEs

 such as IntelliJ IDEA.

 * The command-line tool "isabelle phabricator_setup" facilitates

 self-hosting of the Phabricator software-development platform, with

 support for Git, Mercurial, Subversion repositories. This helps to avoid

 monoculture and to escape the gravity of centralized version control by

 Github and/or Bitbucket. For further documentation, see chapter

 "Phabricator server administration" in the "system" manual. A notable

 example installation is https://isabelle-dev.sketis.net/.

 * The command-line tool "isabelle hg_setup" simplifies the setup of

 Mercurial repositories, with hosting via Phabricator or SSH file server

 access.

 * The command-line tool "isabelle imports" has been discontinued: strict

 checking of session directories enforces session-qualified theory names

 in applications -- users are responsible to specify session ROOT entries

 properly.

 * The command-line tool "isabelle dump" and its underlying

 Isabelle/Scala module isabelle.Dump has become more scalable, by

 splitting sessions and supporting a base logic image. Minor

 INCOMPATIBILITY in options and parameters.

 * The command-line tool "isabelle build_docker" has been slightly

 improved: it is now properly documented in the "system" manual.

 * Isabelle/Scala support for the Linux platform (Ubuntu): packages,

 users, system services.

 * Isabelle/Scala support for proof terms (with full type/term

 information) in module isabelle.Term.

 * Isabelle/Scala: more scalable output of YXML files, e.g. relevant for

 "isabelle dump".

 * Theory export via Isabelle/Scala has been reworked. The former "fact"

 name space is now split into individual "thm" items: names are

 potentially indexed, such as "foo" for singleton facts, or "bar(1)",

 "bar(2)", "bar(3)" for multi-facts. Theorem dependencies are now

 exported as well: this spans an overall dependency graph of internal

 inferences; it might help to reconstruct the formal structure of theory

 libraries. See also the module isabelle.Export_Theory in Isabelle/Scala.

 * Theory export of structured specifications, based on internal

 declarations of Spec_Rules by packages like 'definition', 'inductive',

 'primrec', 'function'.

 * Old settings variables ISABELLE_PLATFORM and ISABELLE_WINDOWS_PLATFORM

 have been discontinued -- deprecated since Isabelle2018.

 * More complete x86_64 platform support on macOS, notably Catalina where

 old x86 has been discontinued.

 * Update to GHC stack 2.1.3 with stackage lts-13.19/ghc-8.6.4.

 * Update to OCaml Opam 2.0.6 (using ocaml 4.05.0 as before).

 New in Isabelle2019 (June 2019)

 -------------------------------

 *** General ***

 * The font collection "Isabelle DejaVu" is systematically derived from

 the existing "DejaVu" fonts, with variants "Sans Mono", "Sans", "Serif"

 and styles "Normal", "Bold", "Italic/Oblique", "Bold-Italic/Oblique".

 The DejaVu base fonts are retricted to well-defined Unicode ranges and

 augmented by special Isabelle symbols, taken from the former

 "IsabelleText" font (which is no longer provided separately). The line

 metrics and overall rendering quality is closer to original DejaVu.

 INCOMPATIBILITY with display configuration expecting the old

 "IsabelleText" font: use e.g. "Isabelle DejaVu Sans Mono" instead.

 * The Isabelle fonts render "\<inverse>" properly as superscript "-1".

 * Old-style inner comments (* ... *) within the term language are no

 longer supported (legacy feature in Isabelle2018).

 * Old-style {* verbatim *} tokens are explicitly marked as legacy

 feature and will be removed soon. Use \<open>cartouche\<close> syntax instead, e.g.

 via "isabelle update_cartouches -t" (available since Isabelle2015).

 * Infix operators that begin or end with a "*" are now parenthesized

 without additional spaces, e.g. "(*)" instead of "( * )". Minor

 INCOMPATIBILITY.

 * Mixfix annotations may use cartouches instead of old-style double

 quotes, e.g. (infixl \<open>+\<close> 60). The command-line tool "isabelle update -u

 mixfix_cartouches" allows to update existing theory sources

 automatically.

 * ML setup commands (e.g. 'setup', 'method_setup', 'parse_translation')

 need to provide a closed expression -- without trailing semicolon. Minor

 INCOMPATIBILITY.

 * Commands 'generate_file', 'export_generated_files', and

 'compile_generated_files' support a stateless (PIDE-conformant) model

 for generated sources and compiled binaries of other languages. The

 compilation process is managed in Isabelle/ML, and results exported to

 the session database for further use (e.g. with "isabelle export" or

 "isabelle build -e").

 *** Isabelle/jEdit Prover IDE ***

 * Fonts for the text area, gutter, GUI elements etc. use the "Isabelle

 DejaVu" collection by default, which provides uniform rendering quality

 with the usual Isabelle symbols. Line spacing no longer needs to be

 adjusted: properties for the old IsabelleText font had "Global Options /

 Text Area / Extra vertical line spacing (in pixels): -2", it now

 defaults to 1, but 0 works as well.

 * The jEdit File Browser is more prominent in the default GUI layout of

 Isabelle/jEdit: various virtual file-systems provide access to Isabelle

 resources, notably via "favorites:" (or "Edit Favorites").

 * Further markup and rendering for "plain text" (e.g. informal prose)

 and "raw text" (e.g. verbatim sources). This improves the visual

 appearance of formal comments inside the term language, or in general

 for repeated alternation of formal and informal text.

 * Action "isabelle-export-browser" points the File Browser to the theory

 exports of the current buffer, based on the "isabelle-export:" virtual

 file-system. The directory view needs to be reloaded manually to follow

 ongoing document processing.

 * Action "isabelle-session-browser" points the File Browser to session

 information, based on the "isabelle-session:" virtual file-system. Its

 entries are structured according to chapter / session names, the open

 operation is redirected to the session ROOT file.

 * Support for user-defined file-formats via class isabelle.File_Format

 in Isabelle/Scala (e.g. see isabelle.Bibtex.File_Format), configured via

 the shell function "isabelle_file_format" in etc/settings (e.g. of an

 Isabelle component).

 * System option "jedit_text_overview" allows to disable the text

 overview column.

 * Command-line options "-s" and "-u" of "isabelle jedit" override the

 default for system option "system_heaps" that determines the heap

 storage directory for "isabelle build". Option "-n" is now clearly

 separated from option "-s".

 * The Isabelle/jEdit desktop application uses the same options as

 "isabelle jedit" for its internal "isabelle build" process: the implicit

 option "-o system_heaps" (or "-s") has been discontinued. This reduces

 the potential for surprise wrt. command-line tools.

 * The official download of the Isabelle/jEdit application already

 contains heap images for Isabelle/HOL within its main directory: thus

 the first encounter becomes faster and more robust (e.g. when run from a

 read-only directory).

 * Isabelle DejaVu fonts are available with hinting by default, which is

 relevant for low-resolution displays. This may be disabled via system

 option "isabelle_fonts_hinted = false" in

 $ISABELLE_HOME_USER/etc/preferences -- it occasionally yields better

 results.

 * OpenJDK 11 has quite different font rendering, with better glyph

 shapes and improved sub-pixel anti-aliasing. In some situations results

 might be *worse* than Oracle Java 8, though -- a proper HiDPI / UHD

 display is recommended.

 * OpenJDK 11 supports GTK version 2.2 and 3 (according to system

 property jdk.gtk.version). The factory default is version 3, but

 ISABELLE_JAVA_SYSTEM_OPTIONS includes "-Djdk.gtk.version=2.2" to make

 this more conservative (as in Java 8). Depending on the GTK theme

 configuration, "-Djdk.gtk.version=3" might work better or worse.

 *** Document preparation ***

 * Document markers are formal comments of the form \<^marker>\<open>marker_body\<close> that

 are stripped from document output: the effect is to modify the semantic

 presentation context or to emit markup to the PIDE document. Some

 predefined markers are taken from the Dublin Core Metadata Initiative,

 e.g. \<^marker>\<open>contributor arg\<close> or \<^marker>\<open>license arg\<close> and produce PIDE markup that

 can be retrieved from the document database.

 * Old-style command tags %name are re-interpreted as markers with

 proof-scope \<^marker>\<open>tag (proof) name\<close> and produce LaTeX environments as

 before. Potential INCOMPATIBILITY: multiple markers are composed in

 canonical order, resulting in a reversed list of tags in the

 presentation context.

 * Marker \<^marker>\<open>tag name\<close> does not apply to the proof of a top-level goal

 statement by default (e.g. 'theorem', 'lemma'). This is a subtle change

 of semantics wrt. old-style %name.

 * In Isabelle/jEdit, the string "\tag" may be completed to a "\<^marker>\<open>tag \<close>"

 template.

 * Document antiquotation option "cartouche" indicates if the output

 should be delimited as cartouche; this takes precedence over the

 analogous option "quotes".

 * Many document antiquotations are internally categorized as "embedded"

 and expect one cartouche argument, which is typically used with the

 \<^control>\<open>cartouche\<close> notation (e.g. \<^term>\<open>\<lambda>x y. x\<close>). The cartouche

 delimiters are stripped in output of the source (antiquotation option

 "source"), but it is possible to enforce delimiters via option

 "source_cartouche", e.g. @{term [source_cartouche] \<open>\<lambda>x y. x\<close>}.

 *** Isar ***

 * Implicit cases goal1, goal2, goal3, etc. have been discontinued

 (legacy feature since Isabelle2016).

 * More robust treatment of structural errors: begin/end blocks take

 precedence over goal/proof. This is particularly relevant for the

 headless PIDE session and server.

 * Command keywords of kind thy_decl / thy_goal may be more specifically

 fit into the traditional document model of "definition-statement-proof"

 via thy_defn / thy_stmt / thy_goal_defn / thy_goal_stmt.

 *** HOL ***

 * Command 'export_code' produces output as logical files within the

 theory context, as well as formal session exports that can be

 materialized via command-line tools "isabelle export" or "isabelle build

 -e" (with 'export_files' in the session ROOT). Isabelle/jEdit also

 provides a virtual file-system "isabelle-export:" that can be explored

 in the regular file-browser. A 'file_prefix' argument allows to specify

 an explicit name prefix for the target file (SML, OCaml, Scala) or

 directory (Haskell); the default is "export" with a consecutive number

 within each theory.

 * Command 'export_code': the 'file' argument is now legacy and will be

 removed soon: writing to the physical file-system is not well-defined in

 a reactive/parallel application like Isabelle. The empty 'file' argument

 has been discontinued already: it is superseded by the file-browser in

 Isabelle/jEdit on "isabelle-export:". Minor INCOMPATIBILITY.

 * Command 'code_reflect' no longer supports the 'file' argument: it has

 been superseded by 'file_prefix' for stateless file management as in

 'export_code'. Minor INCOMPATIBILITY.

 * Code generation for OCaml: proper strings are used for literals.

 Minor INCOMPATIBILITY.

 * Code generation for OCaml: Zarith supersedes Nums as library for

 proper integer arithmetic. The library is located via standard

 invocations of "ocamlfind" (via ISABELLE_OCAMLFIND settings variable).

 The environment provided by "isabelle ocaml_setup" already contains this

 tool and the required packages. Minor INCOMPATIBILITY.

 * Code generation for Haskell: code includes for Haskell must contain

 proper module frame, nothing is added magically any longer.

 INCOMPATIBILITY.

 * Code generation: slightly more conventional syntax for 'code_stmts'

 antiquotation. Minor INCOMPATIBILITY.

 * Theory List: the precedence of the list_update operator has changed:

 "f a [n := x]" now needs to be written "(f a)[n := x]".

 * The functions \<Union>, \<Inter>, \<Squnion>, \<Sqinter> (not the corresponding binding operators)

 now have the same precedence as any other prefix function symbol. Minor

 INCOMPATIBILITY.

 * Simplified syntax setup for big operators under image. In rare

 situations, type conversions are not inserted implicitly any longer

 and need to be given explicitly. Auxiliary abbreviations INFIMUM,

 SUPREMUM, UNION, INTER should now rarely occur in output and are just

 retained as migration auxiliary. Abbreviations MINIMUM and MAXIMUM

 are gone INCOMPATIBILITY.

 * The simplifier uses image_cong_simp as a congruence rule. The historic

 and not really well-formed congruence rules INF_cong*, SUP_cong*, are

 not used by default any longer. INCOMPATIBILITY; consider using declare

 image_cong_simp [cong del] in extreme situations.

 * INF_image and SUP_image are no default simp rules any longer.

 INCOMPATIBILITY, prefer image_comp as simp rule if needed.

 * Strong congruence rules (with =simp=> in the premises) for constant f

 are now uniformly called f_cong_simp, in accordance with congruence

 rules produced for mappers by the datatype package. INCOMPATIBILITY.

 * Retired lemma card_Union_image; use the simpler card_UN_disjoint

 instead. INCOMPATIBILITY.

 * Facts sum_mset.commute and prod_mset.commute have been renamed to

 sum_mset.swap and prod_mset.swap, similarly to sum.swap and prod.swap.

 INCOMPATIBILITY.

 * ML structure Inductive: slightly more conventional naming schema.

 Minor INCOMPATIBILITY.

 * ML: Various _global variants of specification tools have been removed.

 Minor INCOMPATIBILITY, prefer combinators

 Named_Target.theory_map[_result] to lift specifications to the global

 theory level.

 * Theory HOL-Library.Simps_Case_Conv: 'case_of_simps' now supports

 overlapping and non-exhaustive patterns and handles arbitrarily nested

 patterns. It uses on the same algorithm as HOL-Library.Code_Lazy, which

 assumes sequential left-to-right pattern matching. The generated

 equation no longer tuples the arguments on the right-hand side.

 INCOMPATIBILITY.

 * Theory HOL-Library.Multiset: the \<Union># operator now has the same

 precedence as any other prefix function symbol.

 * Theory HOL-Library.Cardinal_Notations has been discontinued in favor

 of the bundle cardinal_syntax (available in theory Main). Minor

 INCOMPATIBILITY.

 * Session HOL-Library and HOL-Number_Theory: Exponentiation by squaring,

 used for computing powers in class "monoid_mult" and modular

 exponentiation.

 * Session HOL-Computational_Algebra: Formal Laurent series and overhaul

 of Formal power series.

 * Session HOL-Number_Theory: More material on residue rings in

 Carmichael's function, primitive roots, more properties for "ord".

 * Session HOL-Analysis: Better organization and much more material

 at the level of abstract topological spaces.

 * Session HOL-Algebra: Free abelian groups, etc., ported from HOL Light;

  algebraic closure of a field by de Vilhena and Baillon.

 * Session HOL-Homology has been added. It is a port of HOL Light's

 homology library, with new proofs of "invariance of domain" and related

 results.

 * Session HOL-SPARK: .prv files are no longer written to the

 file-system, but exported to the session database. Results may be

 retrieved via "isabelle build -e HOL-SPARK-Examples" on the

 command-line.

 * Sledgehammer:

   - The URL for SystemOnTPTP, which is used by remote provers, has been

     updated.

   - The machine-learning-based filter MaSh has been optimized to take

     less time (in most cases).

 * SMT: reconstruction is now possible using the SMT solver veriT.

 * Session HOL-Word:

   * New theory More_Word as comprehensive entrance point.

   * Merged type class bitss into type class bits.

   INCOMPATIBILITY.

 *** ML ***

 * Command 'generate_file' allows to produce sources for other languages,

 with antiquotations in the Isabelle context (only the control-cartouche

 form). The default "cartouche" antiquotation evaluates an ML expression

 of type string and inlines the result as a string literal of the target

 language. For example, this works for Haskell as follows:

   generate_file "Pure.hs" = \<open>

   module Isabelle.Pure where

     allConst, impConst, eqConst :: String

     allConst = \<open>\<^const_name>\<open>Pure.all\<close>\<close>

     impConst = \<open>\<^const_name>\<open>Pure.imp\<close>\<close>

     eqConst = \<open>\<^const_name>\<open>Pure.eq\<close>\<close>

   \<close>

 See also commands 'export_generated_files' and 'compile_generated_files'

 to use the results.

 * ML evaluation (notably via command 'ML' or 'ML_file') is subject to

 option ML_environment to select a named environment, such as "Isabelle"

 for Isabelle/ML, or "SML" for official Standard ML.

 * ML antiquotation @{master_dir} refers to the master directory of the

 underlying theory, i.e. the directory of the theory file.

 * ML antiquotation @{verbatim} inlines its argument as string literal,

 preserving newlines literally. The short form \<^verbatim>\<open>abc\<close> is particularly

 useful.

 * Local_Theory.reset is no longer available in user space. Regular

 definitional packages should use balanced blocks of

 Local_Theory.open_target versus Local_Theory.close_target instead, or

 the Local_Theory.subtarget(_result) combinator. Rare INCOMPATIBILITY.

 * Original PolyML.pointerEq is retained as a convenience for tools that

 don't use Isabelle/ML (where this is called "pointer_eq").

 *** System ***

 * Update to OpenJDK 11: the current long-term support version of Java.

 * Update to Poly/ML 5.8 allows to use the native x86_64 platform without

 the full overhead of 64-bit values everywhere. This special x86_64_32

 mode provides up to 16GB ML heap, while program code and stacks are

 allocated elsewhere. Thus approx. 5 times more memory is available for

 applications compared to old x86 mode (which is no longer used by

 Isabelle). The switch to the x86_64 CPU architecture also avoids

 compatibility problems with Linux and macOS, where 32-bit applications

 are gradually phased out.

 * System option "checkpoint" has been discontinued: obsolete thanks to

 improved memory management in Poly/ML.

 * System option "system_heaps" determines where to store the session

 image of "isabelle build" (and other tools using that internally).

 Former option "-s" is superseded by option "-o system_heaps".

 INCOMPATIBILITY in command-line syntax.

 * Session directory $ISABELLE_HOME/src/Tools/Haskell provides some

 source modules for Isabelle tools implemented in Haskell, notably for

 Isabelle/PIDE.

 * The command-line tool "isabelle build -e" retrieves theory exports

 from the session build database, using 'export_files' in session ROOT

 entries.

 * The command-line tool "isabelle update" uses Isabelle/PIDE in

 batch-mode to update theory sources based on semantic markup produced in

 Isabelle/ML. Actual updates depend on system options that may be enabled

 via "-u OPT" (for "update_OPT"), see also $ISABELLE_HOME/etc/options

 section "Theory update". Theory sessions are specified as in "isabelle

 dump".

 * The command-line tool "isabelle update -u control_cartouches" changes

 antiquotations into control-symbol format (where possible): @{NAME}

 becomes \<^NAME> and @{NAME ARG} becomes \<^NAME>\<open>ARG\<close>.

 * Support for Isabelle command-line tools defined in Isabelle/Scala.

 Instances of class Isabelle_Scala_Tools may be configured via the shell

 function "isabelle_scala_tools" in etc/settings (e.g. of an Isabelle

 component).

 * Isabelle Server command "use_theories" supports "nodes_status_delay"

 for continuous output of node status information. The time interval is

 specified in seconds; a negative value means it is disabled (default).

 * Isabelle Server command "use_theories" terminates more robustly in the

 presence of structurally broken sources: full consolidation of theories

 is no longer required.

 * OCaml tools and libraries are now accesed via ISABELLE_OCAMLFIND,

 which needs to point to a suitable version of "ocamlfind" (e.g. via

 OPAM, see below). INCOMPATIBILITY: settings variables ISABELLE_OCAML and

 ISABELLE_OCAMLC are no longer supported.

 * Support for managed installations of Glasgow Haskell Compiler and

 OCaml via the following command-line tools:

   isabelle ghc_setup

   isabelle ghc_stack

   isabelle ocaml_setup

   isabelle ocaml_opam

 The global installation state is determined by the following settings

 (and corresponding directory contents):

   ISABELLE_STACK_ROOT

   ISABELLE_STACK_RESOLVER

   ISABELLE_GHC_VERSION

   ISABELLE_OPAM_ROOT

   ISABELLE_OCAML_VERSION

 After setup, the following Isabelle settings are automatically

 redirected (overriding existing user settings):

   ISABELLE_GHC

   ISABELLE_OCAMLFIND

 The old meaning of these settings as locally installed executables may

 be recovered by purging the directories ISABELLE_STACK_ROOT /

 ISABELLE_OPAM_ROOT, or by resetting these variables in

 $ISABELLE_HOME_USER/etc/settings.

 New in Isabelle2018 (August 2018)

 ---------------------------------

 *** General ***

 * Session-qualified theory names are mandatory: it is no longer possible

 to refer to unqualified theories from the parent session.

 INCOMPATIBILITY for old developments that have not been updated to

 Isabelle2017 yet (using the "isabelle imports" tool).

 * Only the most fundamental theory names are global, usually the entry

 points to major logic sessions: Pure, Main, Complex_Main, HOLCF, IFOL,

 FOL, ZF, ZFC etc. INCOMPATIBILITY, need to use qualified names for

 formerly global "HOL-Probability.Probability" and "HOL-SPARK.SPARK".

 * Global facts need to be closed: no free variables and no hypotheses.

 Rare INCOMPATIBILITY.

 * Facts stemming from locale interpretation are subject to lazy

 evaluation for improved performance. Rare INCOMPATIBILITY: errors

 stemming from interpretation morphisms might be deferred and thus

 difficult to locate; enable system option "strict_facts" temporarily to

 avoid this.

 * Marginal comments need to be written exclusively in the new-style form

 "\<comment> \<open>text\<close>", old ASCII variants like "-- {* ... *}" are no longer

 supported. INCOMPATIBILITY, use the command-line tool "isabelle

 update_comments" to update existing theory files.

 * Old-style inner comments (* ... *) within the term language are legacy

 and will be discontinued soon: use formal comments "\<comment> \<open>...\<close>" or "\<^cancel>\<open>...\<close>"

 instead.

 * The "op <infix-op>" syntax for infix operators has been replaced by

 "(<infix-op>)". If <infix-op> begins or ends with a "*", there needs to

 be a space between the "*" and the corresponding parenthesis.

 INCOMPATIBILITY, use the command-line tool "isabelle update_op" to

 convert theory and ML files to the new syntax. Because it is based on

 regular expression matching, the result may need a bit of manual

 postprocessing. Invoking "isabelle update_op" converts all files in the

 current directory (recursively). In case you want to exclude conversion

 of ML files (because the tool frequently also converts ML's "op"

 syntax), use option "-m".

 * Theory header 'abbrevs' specifications need to be separated by 'and'.

 INCOMPATIBILITY.

 * Command 'external_file' declares the formal dependency on the given

 file name, such that the Isabelle build process knows about it, but

 without specific Prover IDE management.

 * Session ROOT entries no longer allow specification of 'files'. Rare

 INCOMPATIBILITY, use command 'external_file' within a proper theory

 context.

 * Session root directories may be specified multiple times: each

 accessible ROOT file is processed only once. This facilitates

 specification of $ISABELLE_HOME_USER/ROOTS or command-line options like

 -d or -D for "isabelle build" and "isabelle jedit". Example:

   isabelle build -D '~~/src/ZF'

 * The command 'display_drafts' has been discontinued. INCOMPATIBILITY,

 use action "isabelle.draft" (or "print") in Isabelle/jEdit instead.

 * In HTML output, the Isabelle symbol "\<hyphen>" is rendered as explicit

 Unicode hyphen U+2010, to avoid unclear meaning of the old "soft hyphen"

 U+00AD. Rare INCOMPATIBILITY, e.g. copy-paste of historic Isabelle HTML

 output.

 *** Isabelle/jEdit Prover IDE ***

 * The command-line tool "isabelle jedit" provides more flexible options

 for session management:

   - option -R builds an auxiliary logic image with all theories from

     other sessions that are not already present in its parent

   - option -S is like -R, with a focus on the selected session and its

     descendants (this reduces startup time for big projects like AFP)

   - option -A specifies an alternative ancestor session for options -R

     and -S

   - option -i includes additional sessions into the name-space of

     theories

   Examples:

     isabelle jedit -R HOL-Number_Theory

     isabelle jedit -R HOL-Number_Theory -A HOL

     isabelle jedit -d '$AFP' -S Formal_SSA -A HOL

     isabelle jedit -d '$AFP' -S Formal_SSA -A HOL-Analysis

     isabelle jedit -d '$AFP' -S Formal_SSA -A HOL-Analysis -i CryptHOL

 * PIDE markup for session ROOT files: allows to complete session names,

 follow links to theories and document files etc.

 * Completion supports theory header imports, using theory base name.

 E.g. "Prob" may be completed to "HOL-Probability.Probability".

 * Named control symbols (without special Unicode rendering) are shown as

 bold-italic keyword. This is particularly useful for the short form of

 antiquotations with control symbol: \<^name>\<open>argument\<close>. The action

 "isabelle.antiquoted_cartouche" turns an antiquotation with 0 or 1

 arguments into this format.

 * Completion provides templates for named symbols with arguments,

 e.g. "\<comment> \<open>ARGUMENT\<close>" or "\<^emph>\<open>ARGUMENT\<close>".

 * Slightly more parallel checking, notably for high priority print

 functions (e.g. State output).

 * The view title is set dynamically, according to the Isabelle

 distribution and the logic session name. The user can override this via

 set-view-title (stored persistently in $JEDIT_SETTINGS/perspective.xml).

 * System options "spell_checker_include" and "spell_checker_exclude"

 supersede former "spell_checker_elements" to determine regions of text

 that are subject to spell-checking. Minor INCOMPATIBILITY.

 * Action "isabelle.preview" is able to present more file formats,

 notably bibtex database files and ML files.

 * Action "isabelle.draft" is similar to "isabelle.preview", but shows a

 plain-text document draft. Both are available via the menu "Plugins /

 Isabelle".

 * When loading text files, the Isabelle symbols encoding UTF-8-Isabelle

 is only used if there is no conflict with existing Unicode sequences in

 the file. Otherwise, the fallback encoding is plain UTF-8 and Isabelle

 symbols remain in literal \<symbol> form. This avoids accidental loss of

 Unicode content when saving the file.

 * Bibtex database files (.bib) are semantically checked.

 * Update to jedit-5.5.0, the latest release.

 *** Isabelle/VSCode Prover IDE ***

 * HTML preview of theories and other file-formats similar to

 Isabelle/jEdit.

 * Command-line tool "isabelle vscode_server" accepts the same options

 -A, -R, -S, -i for session selection as "isabelle jedit". This is

 relevant for isabelle.args configuration settings in VSCode. The former

 option -A (explore all known session files) has been discontinued: it is

 enabled by default, unless option -S is used to focus on a particular

 spot in the session structure. INCOMPATIBILITY.

 *** Document preparation ***

 * Formal comments work uniformly in outer syntax, inner syntax (term

 language), Isabelle/ML and some other embedded languages of Isabelle.

 See also "Document comments" in the isar-ref manual. The following forms

 are supported:

   - marginal text comment: \<comment> \<open>\<dots>\<close>

   - canceled source: \<^cancel>\<open>\<dots>\<close>

   - raw LaTeX: \<^latex>\<open>\<dots>\<close>

 * Outside of the inner theory body, the default presentation context is

 theory Pure. Thus elementary antiquotations may be used in markup

 commands (e.g. 'chapter', 'section', 'text') and formal comments.

 * System option "document_tags" specifies alternative command tags. This

 is occasionally useful to control the global visibility of commands via

 session options (e.g. in ROOT).

 * Document markup commands ('section', 'text' etc.) are implicitly

 tagged as "document" and visible by default. This avoids the application

 of option "document_tags" to these commands.

 * Isabelle names are mangled into LaTeX macro names to allow the full

 identifier syntax with underscore, prime, digits. This is relevant for

 antiquotations in control symbol notation, e.g. \<^const_name> becomes

 \isactrlconstUNDERSCOREname.

 * Document preparation with skip_proofs option now preserves the content

 more accurately: only terminal proof steps ('by' etc.) are skipped.

 * Document antiquotation @{theory name} requires the long

 session-qualified theory name: this is what users reading the text

 normally need to import.

 * Document antiquotation @{session name} checks and prints the given

 session name verbatim.

 * Document antiquotation @{cite} now checks the given Bibtex entries

 against the Bibtex database files -- only in batch-mode session builds.

 * Command-line tool "isabelle document" has been re-implemented in

 Isabelle/Scala, with simplified arguments and explicit errors from the

 latex and bibtex process. Minor INCOMPATIBILITY.

 * Session ROOT entry: empty 'document_files' means there is no document

 for this session. There is no need to specify options [document = false]

 anymore.

 *** Isar ***

 * Command 'interpret' no longer exposes resulting theorems as literal

 facts, notably for the \<open>prop\<close> notation or the "fact" proof method. This

 improves modularity of proofs and scalability of locale interpretation.

 Rare INCOMPATIBILITY, need to refer to explicitly named facts instead

 (e.g. use 'find_theorems' or 'try' to figure this out).

 * The old 'def' command has been discontinued (legacy since

 Isbelle2016-1). INCOMPATIBILITY, use 'define' instead -- usually with

 object-logic equality or equivalence.

 *** Pure ***

 * The inner syntax category "sort" now includes notation "_" for the

 dummy sort: it is effectively ignored in type-inference.

 * Rewrites clauses (keyword 'rewrites') were moved into the locale

 expression syntax, where they are part of locale instances. In

 interpretation commands rewrites clauses now need to occur before 'for'

 and 'defines'. Rare INCOMPATIBILITY; definitions immediately subject to

 rewriting may need to be pulled up into the surrounding theory.

 * For 'rewrites' clauses, if activating a locale instance fails, fall

 back to reading the clause first. This helps avoid qualification of

 locale instances where the qualifier's sole purpose is avoiding

 duplicate constant declarations.

 * Proof method "simp" now supports a new modifier "flip:" followed by a

 list of theorems. Each of these theorems is removed from the simpset

 (without warning if it is not there) and the symmetric version of the

 theorem (i.e. lhs and rhs exchanged) is added to the simpset. For "auto"

 and friends the modifier is "simp flip:".

 *** HOL ***

 * Sledgehammer: bundled version of "vampire" (for non-commercial users)

 helps to avoid fragility of "remote_vampire" service.

 * Clarified relationship of characters, strings and code generation:

   - Type "char" is now a proper datatype of 8-bit values.

   - Conversions "nat_of_char" and "char_of_nat" are gone; use more

     general conversions "of_char" and "char_of" with suitable type

     constraints instead.

   - The zero character is just written "CHR 0x00", not "0" any longer.

   - Type "String.literal" (for code generation) is now isomorphic to

     lists of 7-bit (ASCII) values; concrete values can be written as

     "STR ''...''" for sequences of printable characters and "STR 0x..."

     for one single ASCII code point given as hexadecimal numeral.

   - Type "String.literal" supports concatenation "... + ..." for all

     standard target languages.

   - Theory HOL-Library.Code_Char is gone; study the explanations

     concerning "String.literal" in the tutorial on code generation to

     get an idea how target-language string literals can be converted to

     HOL string values and vice versa.

   - Session Imperative-HOL: operation "raise" directly takes a value of

     type "String.literal" as argument, not type "string".

 INCOMPATIBILITY.

 * Code generation: Code generation takes an explicit option

 "case_insensitive" to accomodate case-insensitive file systems.

 * Abstract bit operations as part of Main: push_bit, take_bit, drop_bit.

 * New, more general, axiomatization of complete_distrib_lattice. The

 former axioms:

   "sup x (Inf X) = Inf (sup x ` X)" and "inf x (Sup X) = Sup (inf x ` X)"

 are replaced by:

   "Inf (Sup ` A) <= Sup (Inf ` {f ` A | f . (! Y \<in> A . f Y \<in> Y)})"

 The instantiations of sets and functions as complete_distrib_lattice are

 moved to Hilbert_Choice.thy because their proofs need the Hilbert choice

 operator. The dual of this property is also proved in theory

 HOL.Hilbert_Choice.

 * New syntax for the minimum/maximum of a function over a finite set:

 MIN x\<in>A. B and even MIN x. B (only useful for finite types), also MAX.

 * Clarifed theorem names:

   Min.antimono ~> Min.subset_imp

   Max.antimono ~> Max.subset_imp

 Minor INCOMPATIBILITY.

 * SMT module:

   - The 'smt_oracle' option is now necessary when using the 'smt' method

     with a solver other than Z3. INCOMPATIBILITY.

   - The encoding to first-order logic is now more complete in the

     presence of higher-order quantifiers. An 'smt_explicit_application'

     option has been added to control this. INCOMPATIBILITY.

 * Facts sum.commute(_restrict) and prod.commute(_restrict) renamed to

 sum.swap(_restrict) and prod.swap(_restrict), to avoid name clashes on

 interpretation of abstract locales. INCOMPATIBILITY.

 * Predicate coprime is now a real definition, not a mere abbreviation.

 INCOMPATIBILITY.

 * Predicate pairwise_coprime abolished, use "pairwise coprime" instead.

 INCOMPATIBILITY.

 * The relator rel_filter on filters has been strengthened to its

 canonical categorical definition with better properties.

 INCOMPATIBILITY.

 * Generalized linear algebra involving linear, span, dependent, dim

 from type class real_vector to locales module and vector_space.

 Renamed:

   span_inc ~> span_superset

   span_superset ~> span_base

   span_eq ~> span_eq_iff

 INCOMPATIBILITY.

 * Class linordered_semiring_1 covers zero_less_one also, ruling out

 pathologic instances. Minor INCOMPATIBILITY.

 * Theory HOL.List: functions "sorted_wrt" and "sorted" now compare every

 element in a list to all following elements, not just the next one.

 * Theory HOL.List syntax:

   - filter-syntax "[x <- xs. P]" is no longer output syntax, but only

     input syntax

   - list comprehension syntax now supports tuple patterns in "pat <- xs"

 * Theory Map: "empty" must now be qualified as "Map.empty".

 * Removed nat-int transfer machinery. Rare INCOMPATIBILITY.

 * Fact mod_mult_self4 (on nat) renamed to Suc_mod_mult_self3, to avoid

 clash with fact mod_mult_self4 (on more generic semirings).

 INCOMPATIBILITY.

 * Eliminated some theorem aliasses:

   even_times_iff ~> even_mult_iff

   mod_2_not_eq_zero_eq_one_nat ~> not_mod_2_eq_0_eq_1

   even_of_nat ~> even_int_iff

 INCOMPATIBILITY.

 * Eliminated some theorem duplicate variations:

   - dvd_eq_mod_eq_0_numeral can be replaced by dvd_eq_mod_eq_0

   - mod_Suc_eq_Suc_mod can be replaced by mod_Suc

   - mod_Suc_eq_Suc_mod [symmetrict] can be replaced by mod_simps

   - mod_eq_0_iff can be replaced by mod_eq_0_iff_dvd and dvd_def

   - the witness of mod_eqD can be given directly as "_ div _"

 INCOMPATIBILITY.

 * Classical setup: Assumption "m mod d = 0" (for m d :: nat) is no

 longer aggresively destroyed to "\<exists>q. m = d * q". INCOMPATIBILITY, adding

 "elim!: dvd" to classical proof methods in most situations restores

 broken proofs.

 * Theory HOL-Library.Conditional_Parametricity provides command

 'parametric_constant' for proving parametricity of non-recursive

 definitions. For constants that are not fully parametric the command

 will infer conditions on relations (e.g., bi_unique, bi_total, or type

 class conditions such as "respects 0") sufficient for parametricity. See

 theory HOL-ex.Conditional_Parametricity_Examples for some examples.

 * Theory HOL-Library.Code_Lazy provides a new preprocessor for the code

 generator to generate code for algebraic types with lazy evaluation

 semantics even in call-by-value target languages. See the theories

 HOL-ex.Code_Lazy_Demo and HOL-Codegenerator_Test.Code_Lazy_Test for some

 examples.

 * Theory HOL-Library.Landau_Symbols has been moved here from AFP.

 * Theory HOL-Library.Old_Datatype no longer provides the legacy command

 'old_datatype'. INCOMPATIBILITY.

 * Theory HOL-Computational_Algebra.Polynomial_Factorial does not provide

 instances of rat, real, complex as factorial rings etc. Import

 HOL-Computational_Algebra.Field_as_Ring explicitly in case of need.

 INCOMPATIBILITY.

 * Session HOL-Algebra: renamed (^) to [^] to avoid conflict with new

 infix/prefix notation.

 * Session HOL-Algebra: revamped with much new material. The set of

 isomorphisms between two groups is now denoted iso rather than iso_set.

 INCOMPATIBILITY.

 * Session HOL-Analysis: the Arg function now respects the same interval

 as Ln, namely (-pi,pi]; the old Arg function has been renamed Arg2pi.

 INCOMPATIBILITY.

 * Session HOL-Analysis: the functions zorder, zer_poly, porder and

 pol_poly have been redefined. All related lemmas have been reworked.

 INCOMPATIBILITY.

 * Session HOL-Analysis: infinite products, Moebius functions, the

 Riemann mapping theorem, the Vitali covering theorem,

 change-of-variables results for integration and measures.

 * Session HOL-Real_Asymp: proof method "real_asymp" proves asymptotics

 or real-valued functions (limits, "Big-O", etc.) automatically.

 See also ~~/src/HOL/Real_Asymp/Manual for some documentation.

 * Session HOL-Types_To_Sets: more tool support (unoverload_type combines

 internalize_sorts and unoverload) and larger experimental application

 (type based linear algebra transferred to linear algebra on subspaces).

 *** ML ***

 * Operation Export.export emits theory exports (arbitrary blobs), which

 are stored persistently in the session build database.

 * Command 'ML_export' exports ML toplevel bindings to the global

 bootstrap environment of the ML process. This allows ML evaluation

 without a formal theory context, e.g. in command-line tools like

 "isabelle process".

 *** System ***

 * Mac OS X 10.10 Yosemite is now the baseline version; Mavericks is no

 longer supported.

 * Linux and Windows/Cygwin is for x86_64 only, old 32bit platform

 support has been discontinued.

 * Java runtime is for x86_64 only. Corresponding Isabelle settings have

 been renamed to ISABELLE_TOOL_JAVA_OPTIONS and JEDIT_JAVA_OPTIONS,

 instead of former 32/64 variants. INCOMPATIBILITY.

 * Old settings ISABELLE_PLATFORM and ISABELLE_WINDOWS_PLATFORM should be

 phased out due to unclear preference of 32bit vs. 64bit architecture.

 Explicit GNU bash expressions are now preferred, for example (with

 quotes):

   #Posix executables (Unix or Cygwin), with preference for 64bit

   "${ISABELLE_PLATFORM64:-$ISABELLE_PLATFORM32}"

   #native Windows or Unix executables, with preference for 64bit

   "${ISABELLE_WINDOWS_PLATFORM64:-${ISABELLE_WINDOWS_PLATFORM32:-${ISABELLE_PLATFORM64:-$ISABELLE_PLATFORM32}}}"

   #native Windows (32bit) or Unix executables (preference for 64bit)

   "${ISABELLE_WINDOWS_PLATFORM32:-${ISABELLE_PLATFORM64:-$ISABELLE_PLATFORM32}}"

 * Command-line tool "isabelle build" supports new options:

   - option -B NAME: include session NAME and all descendants

   - option -S: only observe changes of sources, not heap images

   - option -f: forces a fresh build

 * Command-line tool "isabelle build" options -c -x -B refer to

 descendants wrt. the session parent or import graph. Subtle

 INCOMPATIBILITY: options -c -x used to refer to the session parent graph

 only.

 * Command-line tool "isabelle build" takes "condition" options with the

 corresponding environment values into account, when determining the

 up-to-date status of a session.

 * The command-line tool "dump" dumps information from the cumulative

 PIDE session database: many sessions may be loaded into a given logic

 image, results from all loaded theories are written to the output

 directory.

 * Command-line tool "isabelle imports -I" also reports actual session

 imports. This helps to minimize the session dependency graph.

 * The command-line tool "export" and 'export_files' in session ROOT

 entries retrieve theory exports from the session build database.

 * The command-line tools "isabelle server" and "isabelle client" provide

 access to the Isabelle Server: it supports responsive session management

 and concurrent use of theories, based on Isabelle/PIDE infrastructure.

 See also the "system" manual.

 * The command-line tool "isabelle update_comments" normalizes formal

 comments in outer syntax as follows: \<comment> \<open>text\<close> (whith a single space to

 approximate the appearance in document output). This is more specific

 than former "isabelle update_cartouches -c": the latter tool option has

 been discontinued.

 * The command-line tool "isabelle mkroot" now always produces a document

 outline: its options have been adapted accordingly. INCOMPATIBILITY.

 * The command-line tool "isabelle mkroot -I" initializes a Mercurial

 repository for the generated session files.

 * Settings ISABELLE_HEAPS + ISABELLE_BROWSER_INFO (or

 ISABELLE_HEAPS_SYSTEM + ISABELLE_BROWSER_INFO_SYSTEM in "system build

 mode") determine the directory locations of the main build artefacts --

 instead of hard-wired directories in ISABELLE_HOME_USER (or

 ISABELLE_HOME).

 * Settings ISABELLE_PATH and ISABELLE_OUTPUT have been discontinued:

 heap images and session databases are always stored in

 $ISABELLE_HEAPS/$ML_IDENTIFIER (command-line default) or

 $ISABELLE_HEAPS_SYSTEM/$ML_IDENTIFIER (main Isabelle application or

 "isabelle jedit -s" or "isabelle build -s").

 * ISABELLE_LATEX and ISABELLE_PDFLATEX now include platform-specific

 options for improved error reporting. Potential INCOMPATIBILITY with

 unusual LaTeX installations, may have to adapt these settings.

 * Update to Poly/ML 5.7.1 with slightly improved performance and PIDE

 markup for identifier bindings. It now uses The GNU Multiple Precision

 Arithmetic Library (libgmp) on all platforms, notably Mac OS X with

 32/64 bit.

 New in Isabelle2017 (October 2017)

 ----------------------------------

 *** General ***

 * Experimental support for Visual Studio Code (VSCode) as alternative

 Isabelle/PIDE front-end, see also

 https://marketplace.visualstudio.com/items?itemName=makarius.Isabelle2017

 VSCode is a new type of application that continues the concepts of

 "programmer's editor" and "integrated development environment" towards

 fully semantic editing and debugging -- in a relatively light-weight

 manner. Thus it fits nicely on top of the Isabelle/PIDE infrastructure.

 Technically, VSCode is based on the Electron application framework

 (Node.js + Chromium browser + V8), which is implemented in JavaScript

 and TypeScript, while Isabelle/VSCode mainly consists of Isabelle/Scala

 modules around a Language Server implementation.

 * Theory names are qualified by the session name that they belong to.

 This affects imports, but not the theory name space prefix (which is

 just the theory base name as before).

 In order to import theories from other sessions, the ROOT file format

 provides a new 'sessions' keyword. In contrast, a theory that is

 imported in the old-fashioned manner via an explicit file-system path

 belongs to the current session, and might cause theory name conflicts

 later on. Theories that are imported from other sessions are excluded

 from the current session document. The command-line tool "isabelle

 imports" helps to update theory imports.

 * The main theory entry points for some non-HOL sessions have changed,

 to avoid confusion with the global name "Main" of the session HOL. This

 leads to the follow renamings:

   CTT/Main.thy    ~>  CTT/CTT.thy

   ZF/Main.thy     ~>  ZF/ZF.thy

   ZF/Main_ZF.thy  ~>  ZF/ZF.thy

   ZF/Main_ZFC.thy ~>  ZF/ZFC.thy

   ZF/ZF.thy       ~>  ZF/ZF_Base.thy

 INCOMPATIBILITY.

 * Commands 'alias' and 'type_alias' introduce aliases for constants and

 type constructors, respectively. This allows adhoc changes to name-space

 accesses within global or local theory contexts, e.g. within a 'bundle'.

 * Document antiquotations @{prf} and @{full_prf} output proof terms

 (again) in the same way as commands 'prf' and 'full_prf'.

 * Computations generated by the code generator can be embedded directly

 into ML, alongside with @{code} antiquotations, using the following

 antiquotations:

   @{computation ... terms: ... datatypes: ...} :

     ((term -> term) -> 'ml option -> 'a) -> Proof.context -> term -> 'a

   @{computation_conv ... terms: ... datatypes: ...} :

     (Proof.context -> 'ml -> conv) -> Proof.context -> conv

   @{computation_check terms: ... datatypes: ...} : Proof.context -> conv

 See src/HOL/ex/Computations.thy,

 src/HOL/Decision_Procs/Commutative_Ring.thy and

 src/HOL/Decision_Procs/Reflective_Field.thy for examples and the

 tutorial on code generation.

 *** Prover IDE -- Isabelle/Scala/jEdit ***

 * Session-qualified theory imports allow the Prover IDE to process

 arbitrary theory hierarchies independently of the underlying logic

 session image (e.g. option "isabelle jedit -l"), but the directory

 structure needs to be known in advance (e.g. option "isabelle jedit -d"

 or a line in the file $ISABELLE_HOME_USER/ROOTS).

 * The PIDE document model maintains file content independently of the

 status of jEdit editor buffers. Reloading jEdit buffers no longer causes

 changes of formal document content. Theory dependencies are always

 resolved internally, without the need for corresponding editor buffers.

 The system option "jedit_auto_load" has been discontinued: it is

 effectively always enabled.

 * The Theories dockable provides a "Purge" button, in order to restrict

 the document model to theories that are required for open editor

 buffers.

 * The Theories dockable indicates the overall status of checking of each

 entry. When all forked tasks of a theory are finished, the border is

 painted with thick lines; remaining errors in this situation are

 represented by a different border color.

 * Automatic indentation is more careful to avoid redundant spaces in

 intermediate situations. Keywords are indented after input (via typed

 characters or completion); see also option "jedit_indent_input".

 * Action "isabelle.preview" opens an HTML preview of the current theory

 document in the default web browser.

 * Command-line invocation "isabelle jedit -R -l LOGIC" opens the ROOT

 entry of the specified logic session in the editor, while its parent is

 used for formal checking.

 * The main Isabelle/jEdit plugin may be restarted manually (using the

 jEdit Plugin Manager), as long as the "Isabelle Base" plugin remains

 enabled at all times.

 * Update to current jedit-5.4.0.

 *** Pure ***

 * Deleting the last code equations for a particular function using

 [code del] results in function with no equations (runtime abort) rather

 than an unimplemented function (generation time abort). Use explicit

 [[code drop:]] to enforce the latter. Minor INCOMPATIBILITY.

 * Proper concept of code declarations in code.ML:

   - Regular code declarations act only on the global theory level, being

     ignored with warnings if syntactically malformed.

   - Explicitly global code declarations yield errors if syntactically

     malformed.

   - Default code declarations are silently ignored if syntactically

     malformed.

 Minor INCOMPATIBILITY.

 * Clarified and standardized internal data bookkeeping of code

 declarations: history of serials allows to track potentially

 non-monotonous declarations appropriately. Minor INCOMPATIBILITY.

 *** HOL ***

 * The Nunchaku model finder is now part of "Main".

 * SMT module:

   - A new option, 'smt_nat_as_int', has been added to translate 'nat' to

     'int' and benefit from the SMT solver's theory reasoning. It is

     disabled by default.

   - The legacy module "src/HOL/Library/Old_SMT.thy" has been removed.

   - Several small issues have been rectified in the 'smt' command.

 * (Co)datatype package: The 'size_gen_o_map' lemma is no longer

 generated for datatypes with type class annotations. As a result, the

 tactic that derives it no longer fails on nested datatypes. Slight

 INCOMPATIBILITY.

 * Command and antiquotation "value" with modified default strategy:

 terms without free variables are always evaluated using plain evaluation

 only, with no fallback on normalization by evaluation. Minor

 INCOMPATIBILITY.

 * Theories "GCD" and "Binomial" are already included in "Main" (instead

 of "Complex_Main").

 * Constant "surj" is a full input/output abbreviation (again).

 Minor INCOMPATIBILITY.

 * Dropped aliasses RangeP, DomainP for Rangep, Domainp respectively.

 INCOMPATIBILITY.

 * Renamed ii to imaginary_unit in order to free up ii as a variable

 name. The syntax \<i> remains available. INCOMPATIBILITY.

 * Dropped abbreviations transP, antisymP, single_valuedP; use constants

 transp, antisymp, single_valuedp instead. INCOMPATIBILITY.

 * Constant "subseq" in Topological_Spaces has been removed -- it is

 subsumed by "strict_mono". Some basic lemmas specific to "subseq" have

 been renamed accordingly, e.g. "subseq_o" -> "strict_mono_o" etc.

 * Theory List: "sublist" renamed to "nths" in analogy with "nth", and

 "sublisteq" renamed to "subseq". Minor INCOMPATIBILITY.

 * Theory List: new generic function "sorted_wrt".

 * Named theorems mod_simps covers various congruence rules concerning

 mod, replacing former zmod_simps. INCOMPATIBILITY.

 * Swapped orientation of congruence rules mod_add_left_eq,

 mod_add_right_eq, mod_add_eq, mod_mult_left_eq, mod_mult_right_eq,

 mod_mult_eq, mod_minus_eq, mod_diff_left_eq, mod_diff_right_eq,

 mod_diff_eq. INCOMPATIBILITY.

 * Generalized some facts:

     measure_induct_rule

     measure_induct

     zminus_zmod ~> mod_minus_eq

     zdiff_zmod_left ~> mod_diff_left_eq

     zdiff_zmod_right ~> mod_diff_right_eq

     zmod_eq_dvd_iff ~> mod_eq_dvd_iff

 INCOMPATIBILITY.

 * Algebraic type class hierarchy of euclidean (semi)rings in HOL:

 euclidean_(semi)ring, euclidean_(semi)ring_cancel,

 unique_euclidean_(semi)ring; instantiation requires provision of a

 euclidean size.

 * Theory "HOL-Number_Theory.Euclidean_Algorithm" has been reworked:

   - Euclidean induction is available as rule eucl_induct.

   - Constants Euclidean_Algorithm.gcd, Euclidean_Algorithm.lcm,

     Euclidean_Algorithm.Gcd and Euclidean_Algorithm.Lcm allow

     easy instantiation of euclidean (semi)rings as GCD (semi)rings.

   - Coefficients obtained by extended euclidean algorithm are

     available as "bezout_coefficients".

 INCOMPATIBILITY.

 * Theory "Number_Theory.Totient" introduces basic notions about Euler's

 totient function previously hidden as solitary example in theory

 Residues. Definition changed so that "totient 1 = 1" in agreement with

 the literature. Minor INCOMPATIBILITY.

 * New styles in theory "HOL-Library.LaTeXsugar":

   - "dummy_pats" for printing equations with "_" on the lhs;

   - "eta_expand" for printing eta-expanded terms.

 * Theory "HOL-Library.Permutations": theorem bij_swap_ompose_bij has

 been renamed to bij_swap_compose_bij. INCOMPATIBILITY.

 * New theory "HOL-Library.Going_To_Filter" providing the "f going_to F"

 filter for describing points x such that f(x) is in the filter F.

 * Theory "HOL-Library.Formal_Power_Series": constants X/E/L/F have been

 renamed to fps_X/fps_exp/fps_ln/fps_hypergeo to avoid polluting the name

 space. INCOMPATIBILITY.

 * Theory "HOL-Library.FinFun" has been moved to AFP (again).

 INCOMPATIBILITY.

 * Theory "HOL-Library.FuncSet": some old and rarely used ASCII

 replacement syntax has been removed. INCOMPATIBILITY, standard syntax

 with symbols should be used instead. The subsequent commands help to

 reproduce the old forms, e.g. to simplify porting old theories:

 syntax (ASCII)

   "_PiE" :: "pttrn \<Rightarrow> 'a set \<Rightarrow> 'b set \<Rightarrow> ('a \<Rightarrow> 'b) set"  ("(3PIE _:_./ _)" 10)

   "_Pi"  :: "pttrn \<Rightarrow> 'a set \<Rightarrow> 'b set \<Rightarrow> ('a \<Rightarrow> 'b) set"  ("(3PI _:_./ _)" 10)

   "_lam" :: "pttrn \<Rightarrow> 'a set \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> ('a \<Rightarrow> 'b)"  ("(3%_:_./ _)" [0,0,3] 3)

 * Theory "HOL-Library.Multiset": the simprocs on subsets operators of

 multisets have been renamed:

   msetless_cancel_numerals ~> msetsubset_cancel

   msetle_cancel_numerals ~> msetsubset_eq_cancel

 INCOMPATIBILITY.

 * Theory "HOL-Library.Pattern_Aliases" provides input and output syntax

 for pattern aliases as known from Haskell, Scala and ML.

 * Theory "HOL-Library.Uprod" formalizes the type of unordered pairs.

 * Session HOL-Analysis: more material involving arcs, paths, covering

 spaces, innessential maps, retracts, infinite products, simplicial

 complexes. Baire Category theorem. Major results include the Jordan

 Curve Theorem and the Great Picard Theorem.

 * Session HOL-Algebra has been extended by additional lattice theory:

 the Knaster-Tarski fixed point theorem and Galois Connections.

 * Sessions HOL-Computational_Algebra and HOL-Number_Theory: new notions

 of squarefreeness, n-th powers, and prime powers.

 * Session "HOL-Computional_Algebra" covers many previously scattered

 theories, notably Euclidean_Algorithm, Factorial_Ring,

 Formal_Power_Series, Fraction_Field, Fundamental_Theorem_Algebra,

 Normalized_Fraction, Polynomial_FPS, Polynomial, Primes. Minor

 INCOMPATIBILITY.

 *** System ***

 * Isabelle/Scala: the SQL module supports access to relational

 databases, either as plain file (SQLite) or full-scale server

 (PostgreSQL via local port or remote ssh connection).

 * Results of "isabelle build" are recorded as SQLite database (i.e.

 "Application File Format" in the sense of

 https://www.sqlite.org/appfileformat.html). This allows systematic

 access via operations from module Sessions.Store in Isabelle/Scala.

 * System option "parallel_proofs" is 1 by default (instead of more

 aggressive 2). This requires less heap space and avoids burning parallel

 CPU cycles, while full subproof parallelization is enabled for repeated

 builds (according to parallel_subproofs_threshold).

 * System option "record_proofs" allows to change the global

 Proofterm.proofs variable for a session. Regular values are are 0, 1, 2;

 a negative value means the current state in the ML heap image remains

 unchanged.

 * Isabelle settings variable ISABELLE_SCALA_BUILD_OPTIONS has been

 renamed to ISABELLE_SCALAC_OPTIONS. Rare INCOMPATIBILITY.

 * Isabelle settings variables ISABELLE_WINDOWS_PLATFORM,

 ISABELLE_WINDOWS_PLATFORM32, ISABELLE_WINDOWS_PLATFORM64 indicate the

 native Windows platform (independently of the Cygwin installation). This

 is analogous to ISABELLE_PLATFORM, ISABELLE_PLATFORM32,

 ISABELLE_PLATFORM64.

 * Command-line tool "isabelle build_docker" builds a Docker image from

 the Isabelle application bundle for Linux. See also

 https://hub.docker.com/r/makarius/isabelle

 * Command-line tool "isabelle vscode_server" provides a Language Server

 Protocol implementation, e.g. for the Visual Studio Code editor. It

 serves as example for alternative PIDE front-ends.

 * Command-line tool "isabelle imports" helps to maintain theory imports

 wrt. session structure. Examples for the main Isabelle distribution:

   isabelle imports -I -a

   isabelle imports -U -a

   isabelle imports -U -i -a

   isabelle imports -M -a -d '~~/src/Benchmarks'

 New in Isabelle2016-1 (December 2016)

 -------------------------------------

 *** General ***

 * Splitter in proof methods "simp", "auto" and friends:

   - The syntax "split add" has been discontinued, use plain "split",

     INCOMPATIBILITY.

   - For situations with many conditional or case expressions, there is

     an alternative splitting strategy that can be much faster. It is

     selected by writing "split!" instead of "split". It applies safe

     introduction and elimination rules after each split rule. As a

     result the subgoal may be split into several subgoals.

 * Command 'bundle' provides a local theory target to define a bundle

 from the body of specification commands (such as 'declare',

 'declaration', 'notation', 'lemmas', 'lemma'). For example:

 bundle foo

 begin

   declare a [simp]

   declare b [intro]

 end

 * Command 'unbundle' is like 'include', but works within a local theory

 context. Unlike "context includes ... begin", the effect of 'unbundle'

 on the target context persists, until different declarations are given.

 * Simplified outer syntax: uniform category "name" includes long

 identifiers. Former "xname" / "nameref" / "name reference" has been

 discontinued.

 * Embedded content (e.g. the inner syntax of types, terms, props) may be

 delimited uniformly via cartouches. This works better than old-fashioned

 quotes when sub-languages are nested.

 * Mixfix annotations support general block properties, with syntax

 "(\<open>x=a y=b z \<dots>\<close>". Notable property names are "indent", "consistent",

 "unbreakable", "markup". The existing notation "(DIGITS" is equivalent

 to "(\<open>indent=DIGITS\<close>". The former notation "(00" for unbreakable blocks

 is superseded by "(\<open>unbreabable\<close>" --- rare INCOMPATIBILITY.

 * Proof method "blast" is more robust wrt. corner cases of Pure

 statements without object-logic judgment.

 * Commands 'prf' and 'full_prf' are somewhat more informative (again):

 proof terms are reconstructed and cleaned from administrative thm nodes.

 * Code generator: config option "code_timing" triggers measurements of

 different phases of code generation. See src/HOL/ex/Code_Timing.thy for

 examples.

 * Code generator: implicits in Scala (stemming from type class

 instances) are generated into companion object of corresponding type

 class, to resolve some situations where ambiguities may occur.

 * Solve direct: option "solve_direct_strict_warnings" gives explicit

 warnings for lemma statements with trivial proofs.

 *** Prover IDE -- Isabelle/Scala/jEdit ***

 * More aggressive flushing of machine-generated input, according to

 system option editor_generated_input_delay (in addition to existing

 editor_input_delay for regular user edits). This may affect overall PIDE

 reactivity and CPU usage.

 * Syntactic indentation according to Isabelle outer syntax. Action

 "indent-lines" (shortcut C+i) indents the current line according to

 command keywords and some command substructure. Action

 "isabelle.newline" (shortcut ENTER) indents the old and the new line

 according to command keywords only; see also option

 "jedit_indent_newline".

 * Semantic indentation for unstructured proof scripts ('apply' etc.) via

 number of subgoals. This requires information of ongoing document

 processing and may thus lag behind, when the user is editing too

 quickly; see also option "jedit_script_indent" and

 "jedit_script_indent_limit".

 * Refined folding mode "isabelle" based on Isar syntax: 'next' and 'qed'

 are treated as delimiters for fold structure; 'begin' and 'end'

 structure of theory specifications is treated as well.

 * Command 'proof' provides information about proof outline with cases,

 e.g. for proof methods "cases", "induct", "goal_cases".

 * Completion templates for commands involving "begin ... end" blocks,

 e.g. 'context', 'notepad'.

 * Sidekick parser "isabelle-context" shows nesting of context blocks

 according to 'begin' and 'end' structure.

 * Highlighting of entity def/ref positions wrt. cursor.

 * Action "isabelle.select-entity" (shortcut CS+ENTER) selects all

 occurrences of the formal entity at the caret position. This facilitates

 systematic renaming.

 * PIDE document markup works across multiple Isar commands, e.g. the

 results established at the end of a proof are properly identified in the

 theorem statement.

 * Cartouche abbreviations work both for " and ` to accomodate typical

 situations where old ASCII notation may be updated.

 * Dockable window "Symbols" also provides access to 'abbrevs' from the

 outer syntax of the current theory buffer. This provides clickable

 syntax templates, including entries with empty abbrevs name (which are

 inaccessible via keyboard completion).

 * IDE support for the Isabelle/Pure bootstrap process, with the

 following independent stages:

   src/Pure/ROOT0.ML

   src/Pure/ROOT.ML

   src/Pure/Pure.thy

   src/Pure/ML_Bootstrap.thy

 The ML ROOT files act like quasi-theories in the context of theory

 ML_Bootstrap: this allows continuous checking of all loaded ML files.

 The theory files are presented with a modified header to import Pure

 from the running Isabelle instance. Results from changed versions of

 each stage are *not* propagated to the next stage, and isolated from the

 actual Isabelle/Pure that runs the IDE itself. The sequential

 dependencies of the above files are only observed for batch build.

 * Isabelle/ML and Standard ML files are presented in Sidekick with the

 tree structure of section headings: this special comment format is

 described in "implementation" chapter 0, e.g. (*** section ***).

 * Additional abbreviations for syntactic completion may be specified

 within the theory header as 'abbrevs'. The theory syntax for 'keywords'

 has been simplified accordingly: optional abbrevs need to go into the

 new 'abbrevs' section.

 * Global abbreviations via $ISABELLE_HOME/etc/abbrevs and

 $ISABELLE_HOME_USER/etc/abbrevs are no longer supported. Minor

 INCOMPATIBILITY, use 'abbrevs' within theory header instead.

 * Action "isabelle.keymap-merge" asks the user to resolve pending

 Isabelle keymap changes that are in conflict with the current jEdit

 keymap; non-conflicting changes are always applied implicitly. This

 action is automatically invoked on Isabelle/jEdit startup and thus

 increases chances that users see new keyboard shortcuts when re-using

 old keymaps.

 * ML and document antiquotations for file-systems paths are more uniform

 and diverse:

   @{path NAME}   -- no file-system check

   @{file NAME}   -- check for plain file

   @{dir NAME}    -- check for directory

 Minor INCOMPATIBILITY, former uses of @{file} and @{file_unchecked} may

 have to be changed.

 *** Document preparation ***

 * New symbol \<circle>, e.g. for temporal operator.

 * New document and ML antiquotation @{locale} for locales, similar to

 existing antiquotation @{class}.

 * Mixfix annotations support delimiters like \<^control>\<open>cartouche\<close> --

 this allows special forms of document output.

 * Raw LaTeX output now works via \<^latex>\<open>...\<close> instead of raw control

 symbol \<^raw:...>. INCOMPATIBILITY, notably for LaTeXsugar.thy and its

 derivatives.

 * \<^raw:...> symbols are no longer supported.

 * Old 'header' command is no longer supported (legacy since

 Isabelle2015).

 *** Isar ***

 * Many specification elements support structured statements with 'if' /

 'for' eigen-context, e.g. 'axiomatization', 'abbreviation',

 'definition', 'inductive', 'function'.

 * Toplevel theorem statements support eigen-context notation with 'if' /

 'for' (in postfix), which corresponds to 'assumes' / 'fixes' in the

 traditional long statement form (in prefix). Local premises are called

 "that" or "assms", respectively. Empty premises are *not* bound in the

 context: INCOMPATIBILITY.

 * Command 'define' introduces a local (non-polymorphic) definition, with

 optional abstraction over local parameters. The syntax resembles

 'definition' and 'obtain'. It fits better into the Isar language than

 old 'def', which is now a legacy feature.

 * Command 'obtain' supports structured statements with 'if' / 'for'

 context.

 * Command '\<proof>' is an alias for 'sorry', with different

 typesetting. E.g. to produce proof holes in examples and documentation.

 * The defining position of a literal fact \<open>prop\<close> is maintained more

 carefully, and made accessible as hyperlink in the Prover IDE.

 * Commands 'finally' and 'ultimately' used to expose the result as

 literal fact: this accidental behaviour has been discontinued. Rare

 INCOMPATIBILITY, use more explicit means to refer to facts in Isar.

 * Command 'axiomatization' has become more restrictive to correspond

 better to internal axioms as singleton facts with mandatory name. Minor

 INCOMPATIBILITY.

 * Proof methods may refer to the main facts via the dynamic fact

 "method_facts". This is particularly useful for Eisbach method

 definitions.

 * Proof method "use" allows to modify the main facts of a given method

 expression, e.g.

   (use facts in simp)

   (use facts in \<open>simp add: ...\<close>)

 * The old proof method "default" has been removed (legacy since

 Isabelle2016). INCOMPATIBILITY, use "standard" instead.

 *** Pure ***

 * Pure provides basic versions of proof methods "simp" and "simp_all"

 that only know about meta-equality (==). Potential INCOMPATIBILITY in

 theory imports that merge Pure with e.g. Main of Isabelle/HOL: the order

 is relevant to avoid confusion of Pure.simp vs. HOL.simp.

 * The command 'unfolding' and proof method "unfold" include a second

 stage where given equations are passed through the attribute "abs_def"

 before rewriting. This ensures that definitions are fully expanded,

 regardless of the actual parameters that are provided. Rare

 INCOMPATIBILITY in some corner cases: use proof method (simp only:)

 instead, or declare [[unfold_abs_def = false]] in the proof context.

 * Type-inference improves sorts of newly introduced type variables for

 the object-logic, using its base sort (i.e. HOL.type for Isabelle/HOL).

 Thus terms like "f x" or "\<And>x. P x" without any further syntactic context

 produce x::'a::type in HOL instead of x::'a::{} in Pure. Rare

 INCOMPATIBILITY, need to provide explicit type constraints for Pure

 types where this is really intended.

 *** HOL ***

 * New proof method "argo" using the built-in Argo solver based on SMT

 technology. The method can be used to prove goals of quantifier-free

 propositional logic, goals based on a combination of quantifier-free

 propositional logic with equality, and goals based on a combination of

 quantifier-free propositional logic with linear real arithmetic

 including min/max/abs. See HOL/ex/Argo_Examples.thy for examples.

 * The new "nunchaku" command integrates the Nunchaku model finder. The

 tool is experimental. See ~~/src/HOL/Nunchaku/Nunchaku.thy for details.

 * Metis: The problem encoding has changed very slightly. This might

 break existing proofs. INCOMPATIBILITY.

 * Sledgehammer:

   - The MaSh relevance filter is now faster than before.

   - Produce syntactically correct Vampire 4.0 problem files.

 * (Co)datatype package:

   - New commands for defining corecursive functions and reasoning about

     them in "~~/src/HOL/Library/BNF_Corec.thy": 'corec', 'corecursive',

     'friend_of_corec', and 'corecursion_upto'; and 'corec_unique' proof

     method. See 'isabelle doc corec'.

   - The predicator :: ('a \<Rightarrow> bool) \<Rightarrow> 'a F \<Rightarrow> bool is now a first-class

     citizen in bounded natural functors.

   - 'primrec' now allows nested calls through the predicator in addition

     to the map function.

   - 'bnf' automatically discharges reflexive proof obligations.

   - 'bnf' outputs a slightly modified proof obligation expressing rel in

        terms of map and set

        (not giving a specification for rel makes this one reflexive).

   - 'bnf' outputs a new proof obligation expressing pred in terms of set

        (not giving a specification for pred makes this one reflexive).

     INCOMPATIBILITY: manual 'bnf' declarations may need adjustment.

   - Renamed lemmas:

       rel_prod_apply ~> rel_prod_inject

       pred_prod_apply ~> pred_prod_inject

     INCOMPATIBILITY.

   - The "size" plugin has been made compatible again with locales.

   - The theorems about "rel" and "set" may have a slightly different (but

     equivalent) form.

     INCOMPATIBILITY.

 * The 'coinductive' command produces a proper coinduction rule for

 mutual coinductive predicates. This new rule replaces the old rule,

 which exposed details of the internal fixpoint construction and was

 hard to use. INCOMPATIBILITY.

 * New abbreviations for negated existence (but not bounded existence):

   \<nexists>x. P x \<equiv> \<not> (\<exists>x. P x)

   \<nexists>!x. P x \<equiv> \<not> (\<exists>!x. P x)

 * The print mode "HOL" for ASCII syntax of binders "!", "?", "?!", "@"

 has been removed for output. It is retained for input only, until it is

 eliminated altogether.

 * The unique existence quantifier no longer provides 'binder' syntax,

 but uses syntax translations (as for bounded unique existence). Thus

 iterated quantification \<exists>!x y. P x y with its slightly confusing

 sequential meaning \<exists>!x. \<exists>!y. P x y is no longer possible. Instead,

 pattern abstraction admits simultaneous unique existence \<exists>!(x, y). P x y

 (analogous to existing notation \<exists>!(x, y)\<in>A. P x y). Potential

 INCOMPATIBILITY in rare situations.

 * Conventional syntax "%(). t" for unit abstractions. Slight syntactic

 INCOMPATIBILITY.

 * Renamed constants and corresponding theorems:

     setsum ~> sum

     setprod ~> prod

     listsum ~> sum_list

     listprod ~> prod_list

 INCOMPATIBILITY.

 * Sligthly more standardized theorem names:

     sgn_times ~> sgn_mult

     sgn_mult' ~> Real_Vector_Spaces.sgn_mult

     divide_zero_left ~> div_0

     zero_mod_left ~> mod_0

     divide_zero ~> div_by_0

     divide_1 ~> div_by_1

     nonzero_mult_divide_cancel_left ~> nonzero_mult_div_cancel_left

     div_mult_self1_is_id ~> nonzero_mult_div_cancel_left

     nonzero_mult_divide_cancel_right ~> nonzero_mult_div_cancel_right

     div_mult_self2_is_id ~> nonzero_mult_div_cancel_right

     is_unit_divide_mult_cancel_left ~> is_unit_div_mult_cancel_left

     is_unit_divide_mult_cancel_right ~> is_unit_div_mult_cancel_right

     mod_div_equality ~> div_mult_mod_eq

     mod_div_equality2 ~> mult_div_mod_eq

     mod_div_equality3 ~> mod_div_mult_eq

     mod_div_equality4 ~> mod_mult_div_eq

     minus_div_eq_mod ~> minus_div_mult_eq_mod

     minus_div_eq_mod2 ~> minus_mult_div_eq_mod

     minus_mod_eq_div ~> minus_mod_eq_div_mult

     minus_mod_eq_div2 ~> minus_mod_eq_mult_div

     div_mod_equality' ~> minus_mod_eq_div_mult [symmetric]

     mod_div_equality' ~> minus_div_mult_eq_mod [symmetric]

     zmod_zdiv_equality ~> mult_div_mod_eq [symmetric]

     zmod_zdiv_equality' ~> minus_div_mult_eq_mod [symmetric]

     Divides.mult_div_cancel ~> minus_mod_eq_mult_div [symmetric]

     mult_div_cancel ~> minus_mod_eq_mult_div [symmetric]

     zmult_div_cancel ~> minus_mod_eq_mult_div [symmetric]

     div_1 ~> div_by_Suc_0

     mod_1 ~> mod_by_Suc_0

 INCOMPATIBILITY.

 * New type class "idom_abs_sgn" specifies algebraic properties

 of sign and absolute value functions.  Type class "sgn_if" has

 disappeared.  Slight INCOMPATIBILITY.

 * Dedicated syntax LENGTH('a) for length of types.

 * Characters (type char) are modelled as finite algebraic type

 corresponding to {0..255}.

   - Logical representation:

     * 0 is instantiated to the ASCII zero character.

     * All other characters are represented as "Char n"

       with n being a raw numeral expression less than 256.

     * Expressions of the form "Char n" with n greater than 255

       are non-canonical.

   - Printing and parsing:

     * Printable characters are printed and parsed as "CHR ''\<dots>''"

       (as before).

     * The ASCII zero character is printed and parsed as "0".

     * All other canonical characters are printed as "CHR 0xXX"

       with XX being the hexadecimal character code.  "CHR n"

       is parsable for every numeral expression n.

     * Non-canonical characters have no special syntax and are

       printed as their logical representation.

   - Explicit conversions from and to the natural numbers are

     provided as char_of_nat, nat_of_char (as before).

   - The auxiliary nibble type has been discontinued.

 INCOMPATIBILITY.

 * Type class "div" with operation "mod" renamed to type class "modulo"

 with operation "modulo", analogously to type class "divide". This

 eliminates the need to qualify any of those names in the presence of

 infix "mod" syntax. INCOMPATIBILITY.

 * Statements and proofs of Knaster-Tarski fixpoint combinators lfp/gfp

 have been clarified. The fixpoint properties are lfp_fixpoint, its

 symmetric lfp_unfold (as before), and the duals for gfp. Auxiliary items

 for the proof (lfp_lemma2 etc.) are no longer exported, but can be

 easily recovered by composition with eq_refl. Minor INCOMPATIBILITY.

 * Constant "surj" is a mere input abbreviation, to avoid hiding an

 equation in term output. Minor INCOMPATIBILITY.

 * Command 'code_reflect' accepts empty constructor lists for datatypes,

 which renders those abstract effectively.

 * Command 'export_code' checks given constants for abstraction

 violations: a small guarantee that given constants specify a safe

 interface for the generated code.

 * Code generation for Scala: ambiguous implicts in class diagrams are

 spelt out explicitly.

 * Static evaluators (Code_Evaluation.static_* in Isabelle/ML) rely on

 explicitly provided auxiliary definitions for required type class

 dictionaries rather than half-working magic. INCOMPATIBILITY, see the

 tutorial on code generation for details.

 * Theory Set_Interval: substantial new theorems on indexed sums and

 products.

 * Locale bijection establishes convenient default simp rules such as

 "inv f (f a) = a" for total bijections.

 * Abstract locales semigroup, abel_semigroup, semilattice,

 semilattice_neutr, ordering, ordering_top, semilattice_order,

 semilattice_neutr_order, comm_monoid_set, semilattice_set,

 semilattice_neutr_set, semilattice_order_set,

 semilattice_order_neutr_set monoid_list, comm_monoid_list,

 comm_monoid_list_set, comm_monoid_mset, comm_monoid_fun use boldified

 syntax uniformly that does not clash with corresponding global syntax.

 INCOMPATIBILITY.

 * Former locale lifting_syntax is now a bundle, which is easier to

 include in a local context or theorem statement, e.g. "context includes

 lifting_syntax begin ... end". Minor INCOMPATIBILITY.

 * Some old / obsolete theorems have been renamed / removed, potential

 INCOMPATIBILITY.

   nat_less_cases  --  removed, use linorder_cases instead

   inv_image_comp  --  removed, use image_inv_f_f instead

   image_surj_f_inv_f  ~>  image_f_inv_f

 * Some theorems about groups and orders have been generalised from

   groups to semi-groups that are also monoids:

     le_add_same_cancel1

     le_add_same_cancel2

     less_add_same_cancel1

     less_add_same_cancel2

     add_le_same_cancel1

     add_le_same_cancel2

     add_less_same_cancel1

     add_less_same_cancel2

 * Some simplifications theorems about rings have been removed, since

   superseeded by a more general version:

     less_add_cancel_left_greater_zero ~> less_add_same_cancel1

     less_add_cancel_right_greater_zero ~> less_add_same_cancel2

     less_eq_add_cancel_left_greater_eq_zero ~> le_add_same_cancel1

     less_eq_add_cancel_right_greater_eq_zero ~> le_add_same_cancel2

     less_eq_add_cancel_left_less_eq_zero ~> add_le_same_cancel1

     less_eq_add_cancel_right_less_eq_zero ~> add_le_same_cancel2

     less_add_cancel_left_less_zero ~> add_less_same_cancel1

     less_add_cancel_right_less_zero ~> add_less_same_cancel2

 INCOMPATIBILITY.

 * Renamed split_if -> if_split and split_if_asm -> if_split_asm to

 resemble the f.split naming convention, INCOMPATIBILITY.

 * Added class topological_monoid.

 * The following theorems have been renamed:

   setsum_left_distrib ~> sum_distrib_right

   setsum_right_distrib ~> sum_distrib_left

 INCOMPATIBILITY.

 * Compound constants INFIMUM and SUPREMUM are mere abbreviations now.

 INCOMPATIBILITY.

 * "Gcd (f ` A)" and "Lcm (f ` A)" are printed with optional

 comprehension-like syntax analogously to "Inf (f ` A)" and "Sup (f `

 A)".

 * Class semiring_Lcd merged into semiring_Gcd. INCOMPATIBILITY.

 * The type class ordered_comm_monoid_add is now called

 ordered_cancel_comm_monoid_add. A new type class ordered_comm_monoid_add

 is introduced as the combination of ordered_ab_semigroup_add +

 comm_monoid_add. INCOMPATIBILITY.

 * Introduced the type classes canonically_ordered_comm_monoid_add and

 dioid.

 * Introduced the type class ordered_ab_semigroup_monoid_add_imp_le. When

 instantiating linordered_semiring_strict and ordered_ab_group_add, an

 explicit instantiation of ordered_ab_semigroup_monoid_add_imp_le might

 be required. INCOMPATIBILITY.

 * Dropped various legacy fact bindings, whose replacements are often

 of a more general type also:

   lcm_left_commute_nat ~> lcm.left_commute

   lcm_left_commute_int ~> lcm.left_commute

   gcd_left_commute_nat ~> gcd.left_commute

   gcd_left_commute_int ~> gcd.left_commute

   gcd_greatest_iff_nat ~> gcd_greatest_iff

   gcd_greatest_iff_int ~> gcd_greatest_iff

   coprime_dvd_mult_nat ~> coprime_dvd_mult

   coprime_dvd_mult_int ~> coprime_dvd_mult

   zpower_numeral_even ~> power_numeral_even

   gcd_mult_cancel_nat ~> gcd_mult_cancel

   gcd_mult_cancel_int ~> gcd_mult_cancel

   div_gcd_coprime_nat ~> div_gcd_coprime

   div_gcd_coprime_int ~> div_gcd_coprime

   zpower_numeral_odd ~> power_numeral_odd

   zero_less_int_conv ~> of_nat_0_less_iff

   gcd_greatest_nat ~> gcd_greatest

   gcd_greatest_int ~> gcd_greatest

   coprime_mult_nat ~> coprime_mult

   coprime_mult_int ~> coprime_mult

   lcm_commute_nat ~> lcm.commute

   lcm_commute_int ~> lcm.commute

   int_less_0_conv ~> of_nat_less_0_iff

   gcd_commute_nat ~> gcd.commute

   gcd_commute_int ~> gcd.commute

   Gcd_insert_nat ~> Gcd_insert

   Gcd_insert_int ~> Gcd_insert

   of_int_int_eq ~> of_int_of_nat_eq

   lcm_least_nat ~> lcm_least

   lcm_least_int ~> lcm_least

   lcm_assoc_nat ~> lcm.assoc

   lcm_assoc_int ~> lcm.assoc

   int_le_0_conv ~> of_nat_le_0_iff

   int_eq_0_conv ~> of_nat_eq_0_iff

   Gcd_empty_nat ~> Gcd_empty

   Gcd_empty_int ~> Gcd_empty

   gcd_assoc_nat ~> gcd.assoc

   gcd_assoc_int ~> gcd.assoc

   zero_zle_int ~> of_nat_0_le_iff

   lcm_dvd2_nat ~> dvd_lcm2

   lcm_dvd2_int ~> dvd_lcm2

   lcm_dvd1_nat ~> dvd_lcm1

   lcm_dvd1_int ~> dvd_lcm1

   gcd_zero_nat ~> gcd_eq_0_iff

   gcd_zero_int ~> gcd_eq_0_iff

   gcd_dvd2_nat ~> gcd_dvd2

   gcd_dvd2_int ~> gcd_dvd2

   gcd_dvd1_nat ~> gcd_dvd1

   gcd_dvd1_int ~> gcd_dvd1

   int_numeral ~> of_nat_numeral

   lcm_ac_nat ~> ac_simps

   lcm_ac_int ~> ac_simps

   gcd_ac_nat ~> ac_simps

   gcd_ac_int ~> ac_simps

   abs_int_eq ~> abs_of_nat

   zless_int ~> of_nat_less_iff

   zdiff_int ~> of_nat_diff

   zadd_int ~> of_nat_add

   int_mult ~> of_nat_mult

   int_Suc ~> of_nat_Suc

   inj_int ~> inj_of_nat

   int_1 ~> of_nat_1

   int_0 ~> of_nat_0

   Lcm_empty_nat ~> Lcm_empty

   Lcm_empty_int ~> Lcm_empty

   Lcm_insert_nat ~> Lcm_insert

   Lcm_insert_int ~> Lcm_insert

   comp_fun_idem_gcd_nat ~> comp_fun_idem_gcd

   comp_fun_idem_gcd_int ~> comp_fun_idem_gcd

   comp_fun_idem_lcm_nat ~> comp_fun_idem_lcm

   comp_fun_idem_lcm_int ~> comp_fun_idem_lcm

   Lcm_eq_0 ~> Lcm_eq_0_I

   Lcm0_iff ~> Lcm_0_iff

   Lcm_dvd_int ~> Lcm_least

   divides_mult_nat ~> divides_mult

   divides_mult_int ~> divides_mult

   lcm_0_nat ~> lcm_0_right

   lcm_0_int ~> lcm_0_right

   lcm_0_left_nat ~> lcm_0_left

   lcm_0_left_int ~> lcm_0_left

   dvd_gcd_D1_nat ~> dvd_gcdD1

   dvd_gcd_D1_int ~> dvd_gcdD1

   dvd_gcd_D2_nat ~> dvd_gcdD2

   dvd_gcd_D2_int ~> dvd_gcdD2

   coprime_dvd_mult_iff_nat ~> coprime_dvd_mult_iff

   coprime_dvd_mult_iff_int ~> coprime_dvd_mult_iff

   realpow_minus_mult ~> power_minus_mult

   realpow_Suc_le_self ~> power_Suc_le_self

   dvd_Gcd, dvd_Gcd_nat, dvd_Gcd_int removed in favour of Gcd_greatest

 INCOMPATIBILITY.

 * Renamed HOL/Quotient_Examples/FSet.thy to

 HOL/Quotient_Examples/Quotient_FSet.thy INCOMPATIBILITY.

 * Session HOL-Library: theory FinFun bundles "finfun_syntax" and

 "no_finfun_syntax" allow to control optional syntax in local contexts;

 this supersedes former theory FinFun_Syntax. INCOMPATIBILITY, e.g. use

 "unbundle finfun_syntax" to imitate import of

 "~~/src/HOL/Library/FinFun_Syntax".

 * Session HOL-Library: theory Multiset_Permutations (executably) defines

 the set of permutations of a given set or multiset, i.e. the set of all

 lists that contain every element of the carrier (multi-)set exactly

 once.

 * Session HOL-Library: multiset membership is now expressed using

 set_mset rather than count.

   - Expressions "count M a > 0" and similar simplify to membership

     by default.

   - Converting between "count M a = 0" and non-membership happens using

     equations count_eq_zero_iff and not_in_iff.

   - Rules count_inI and in_countE obtain facts of the form

     "count M a = n" from membership.

   - Rules count_in_diffI and in_diff_countE obtain facts of the form

     "count M a = n + count N a" from membership on difference sets.

 INCOMPATIBILITY.

 * Session HOL-Library: theory LaTeXsugar uses new-style "dummy_pats" for

 displaying equations in functional programming style --- variables

 present on the left-hand but not on the righ-hand side are replaced by

 underscores.

 * Session HOL-Library: theory Combinator_PER provides combinator to

 build partial equivalence relations from a predicate and an equivalence

 relation.

 * Session HOL-Library: theory Perm provides basic facts about almost

 everywhere fix bijections.

 * Session HOL-Library: theory Normalized_Fraction allows viewing an

 element of a field of fractions as a normalized fraction (i.e. a pair of

 numerator and denominator such that the two are coprime and the

 denominator is normalized wrt. unit factors).

 * Session HOL-NSA has been renamed to HOL-Nonstandard_Analysis.

 * Session HOL-Multivariate_Analysis has been renamed to HOL-Analysis.

 * Session HOL-Analysis: measure theory has been moved here from

 HOL-Probability. When importing HOL-Analysis some theorems need

 additional name spaces prefixes due to name clashes. INCOMPATIBILITY.

 * Session HOL-Analysis: more complex analysis including Cauchy's

 inequality, Liouville theorem, open mapping theorem, maximum modulus

 principle, Residue theorem, Schwarz Lemma.

 * Session HOL-Analysis: Theory of polyhedra: faces, extreme points,

 polytopes, and the Krein–Milman Minkowski theorem.

 * Session HOL-Analysis: Numerous results ported from the HOL Light

 libraries: homeomorphisms, continuous function extensions, invariance of

 domain.

 * Session HOL-Probability: the type of emeasure and nn_integral was

 changed from ereal to ennreal, INCOMPATIBILITY.

   emeasure :: 'a measure \<Rightarrow> 'a set \<Rightarrow> ennreal

   nn_integral :: 'a measure \<Rightarrow> ('a \<Rightarrow> ennreal) \<Rightarrow> ennreal

 * Session HOL-Probability: Code generation and QuickCheck for

 Probability Mass Functions.

 * Session HOL-Probability: theory Random_Permutations contains some

 theory about choosing a permutation of a set uniformly at random and

 folding over a list in random order.

 * Session HOL-Probability: theory SPMF formalises discrete

 subprobability distributions.

 * Session HOL-Library: the names of multiset theorems have been

 normalised to distinguish which ordering the theorems are about

     mset_less_eqI ~> mset_subset_eqI

     mset_less_insertD ~> mset_subset_insertD

     mset_less_eq_count ~> mset_subset_eq_count

     mset_less_diff_self ~> mset_subset_diff_self

     mset_le_exists_conv ~> mset_subset_eq_exists_conv

     mset_le_mono_add_right_cancel ~> mset_subset_eq_mono_add_right_cancel

     mset_le_mono_add_left_cancel ~> mset_subset_eq_mono_add_left_cancel

     mset_le_mono_add ~> mset_subset_eq_mono_add

     mset_le_add_left ~> mset_subset_eq_add_left

     mset_le_add_right ~> mset_subset_eq_add_right

     mset_le_single ~> mset_subset_eq_single

     mset_le_multiset_union_diff_commute ~> mset_subset_eq_multiset_union_diff_commute

     diff_le_self ~> diff_subset_eq_self

     mset_leD ~> mset_subset_eqD

     mset_lessD ~> mset_subsetD

     mset_le_insertD ~> mset_subset_eq_insertD

     mset_less_of_empty ~> mset_subset_of_empty

     mset_less_size ~> mset_subset_size

     wf_less_mset_rel ~> wf_subset_mset_rel

     count_le_replicate_mset_le ~> count_le_replicate_mset_subset_eq

     mset_remdups_le ~> mset_remdups_subset_eq

     ms_lesseq_impl ~> subset_eq_mset_impl

 Some functions have been renamed:

     ms_lesseq_impl -> subset_eq_mset_impl

 * HOL-Library: multisets are now ordered with the multiset ordering

     #\<subseteq># ~> \<le>

     #\<subset># ~> <

     le_multiset ~> less_eq_multiset

     less_multiset ~> le_multiset

 INCOMPATIBILITY.

 * Session HOL-Library: the prefix multiset_order has been discontinued:

 the theorems can be directly accessed. As a consequence, the lemmas

 "order_multiset" and "linorder_multiset" have been discontinued, and the

 interpretations "multiset_linorder" and "multiset_wellorder" have been

 replaced by instantiations. INCOMPATIBILITY.

 * Session HOL-Library: some theorems about the multiset ordering have

 been renamed:

     le_multiset_def ~> less_eq_multiset_def

     less_multiset_def ~> le_multiset_def

     less_eq_imp_le_multiset ~> subset_eq_imp_le_multiset

     mult_less_not_refl ~> mset_le_not_refl

     mult_less_trans ~> mset_le_trans

     mult_less_not_sym ~> mset_le_not_sym

     mult_less_asym ~> mset_le_asym

     mult_less_irrefl ~> mset_le_irrefl

     union_less_mono2{,1,2} ~> union_le_mono2{,1,2}

     le_multiset\<^sub>H\<^sub>O ~> less_eq_multiset\<^sub>H\<^sub>O

     le_multiset_total ~> less_eq_multiset_total

     less_multiset_right_total ~> subset_eq_imp_le_multiset

     le_multiset_empty_left ~> less_eq_multiset_empty_left

     le_multiset_empty_right ~> less_eq_multiset_empty_right

     less_multiset_empty_right ~> le_multiset_empty_left

     less_multiset_empty_left ~> le_multiset_empty_right

     union_less_diff_plus ~> union_le_diff_plus

     ex_gt_count_imp_less_multiset ~> ex_gt_count_imp_le_multiset

     less_multiset_plus_left_nonempty ~> le_multiset_plus_left_nonempty

     le_multiset_plus_right_nonempty ~> le_multiset_plus_right_nonempty

 INCOMPATIBILITY.

 * Session HOL-Library: the lemma mset_map has now the attribute [simp].

 INCOMPATIBILITY.

 * Session HOL-Library: some theorems about multisets have been removed.

 INCOMPATIBILITY, use the following replacements:

     le_multiset_plus_plus_left_iff ~> add_less_cancel_right

     less_multiset_plus_plus_left_iff ~> add_less_cancel_right

     le_multiset_plus_plus_right_iff ~> add_less_cancel_left

     less_multiset_plus_plus_right_iff ~> add_less_cancel_left

     add_eq_self_empty_iff ~> add_cancel_left_right

     mset_subset_add_bothsides ~> subset_mset.add_less_cancel_right

     mset_less_add_bothsides ~> subset_mset.add_less_cancel_right

     mset_le_add_bothsides ~> subset_mset.add_less_cancel_right

     empty_inter ~> subset_mset.inf_bot_left

     inter_empty ~> subset_mset.inf_bot_right

     empty_sup ~> subset_mset.sup_bot_left

     sup_empty ~> subset_mset.sup_bot_right

     bdd_below_multiset ~> subset_mset.bdd_above_bot

     subset_eq_empty ~> subset_mset.le_zero_eq

     le_empty ~> subset_mset.le_zero_eq

     mset_subset_empty_nonempty ~> subset_mset.zero_less_iff_neq_zero

     mset_less_empty_nonempty ~> subset_mset.zero_less_iff_neq_zero

 * Session HOL-Library: some typeclass constraints about multisets have

 been reduced from ordered or linordered to preorder. Multisets have the

 additional typeclasses order_bot, no_top,

 ordered_ab_semigroup_add_imp_le, ordered_cancel_comm_monoid_add,

 linordered_cancel_ab_semigroup_add, and

 ordered_ab_semigroup_monoid_add_imp_le. INCOMPATIBILITY.

 * Session HOL-Library: there are some new simplification rules about

 multisets, the multiset ordering, and the subset ordering on multisets.

 INCOMPATIBILITY.

 * Session HOL-Library: the subset ordering on multisets has now the

 interpretations ordered_ab_semigroup_monoid_add_imp_le and

 bounded_lattice_bot. INCOMPATIBILITY.

 * Session HOL-Library, theory Multiset: single has been removed in favor

 of add_mset that roughly corresponds to Set.insert. Some theorems have

 removed or changed:

   single_not_empty ~> add_mset_not_empty or empty_not_add_mset

   fold_mset_insert ~> fold_mset_add_mset

   image_mset_insert ~> image_mset_add_mset

   union_single_eq_diff

   multi_self_add_other_not_self

   diff_single_eq_union

 INCOMPATIBILITY.

 * Session HOL-Library, theory Multiset: some theorems have been changed

 to use add_mset instead of single:

   mset_add

   multi_self_add_other_not_self

   diff_single_eq_union

   union_single_eq_diff

   union_single_eq_member

   add_eq_conv_diff

   insert_noteq_member

   add_eq_conv_ex

   multi_member_split

   multiset_add_sub_el_shuffle

   mset_subset_eq_insertD

   mset_subset_insertD

   insert_subset_eq_iff

   insert_union_subset_iff

   multi_psub_of_add_self

   inter_add_left1

   inter_add_left2

   inter_add_right1

   inter_add_right2

   sup_union_left1

   sup_union_left2

   sup_union_right1

   sup_union_right2

   size_eq_Suc_imp_eq_union

   multi_nonempty_split

   mset_insort

   mset_update

   mult1I

   less_add

   mset_zip_take_Cons_drop_twice

   rel_mset_Zero

   msed_map_invL

   msed_map_invR

   msed_rel_invL

   msed_rel_invR

   le_multiset_right_total

   multiset_induct

   multiset_induct2_size

   multiset_induct2

 INCOMPATIBILITY.

 * Session HOL-Library, theory Multiset: the definitions of some

 constants have changed to use add_mset instead of adding a single

 element:

   image_mset

   mset

   replicate_mset

   mult1

   pred_mset

   rel_mset'

   mset_insort

 INCOMPATIBILITY.

 * Session HOL-Library, theory Multiset: due to the above changes, the

 attributes of some multiset theorems have been changed:

   insert_DiffM  [] ~> [simp]

   insert_DiffM2 [simp] ~> []

   diff_add_mset_swap [simp]

   fold_mset_add_mset [simp]

   diff_diff_add [simp] (for multisets only)

   diff_cancel [simp] ~> []

   count_single [simp] ~> []

   set_mset_single [simp] ~> []

   size_multiset_single [simp] ~> []

   size_single [simp] ~> []

   image_mset_single [simp] ~> []

   mset_subset_eq_mono_add_right_cancel [simp] ~> []

   mset_subset_eq_mono_add_left_cancel [simp] ~> []

   fold_mset_single [simp] ~> []

   subset_eq_empty [simp] ~> []

   empty_sup [simp] ~> []

   sup_empty [simp] ~> []

   inter_empty [simp] ~> []

   empty_inter [simp] ~> []

 INCOMPATIBILITY.

 * Session HOL-Library, theory Multiset: the order of the variables in

 the second cases of multiset_induct, multiset_induct2_size,

 multiset_induct2 has been changed (e.g. Add A a ~> Add a A).

 INCOMPATIBILITY.

 * Session HOL-Library, theory Multiset: there is now a simplification

 procedure on multisets. It mimics the behavior of the procedure on

 natural numbers. INCOMPATIBILITY.

 * Session HOL-Library, theory Multiset: renamed sums and products of

 multisets:

   msetsum ~> sum_mset

   msetprod ~> prod_mset

 * Session HOL-Library, theory Multiset: the notation for intersection

 and union of multisets have been changed:

   #\<inter> ~> \<inter>#

   #\<union> ~> \<union>#

 INCOMPATIBILITY.

 * Session HOL-Library, theory Multiset: the lemma

 one_step_implies_mult_aux on multisets has been removed, use

 one_step_implies_mult instead. INCOMPATIBILITY.

 * Session HOL-Library: theory Complete_Partial_Order2 provides reasoning

 support for monotonicity and continuity in chain-complete partial orders

 and about admissibility conditions for fixpoint inductions.

 * Session HOL-Library: theory Library/Polynomial contains also

 derivation of polynomials (formerly in Library/Poly_Deriv) but not

 gcd/lcm on polynomials over fields. This has been moved to a separate

 theory Library/Polynomial_GCD_euclidean.thy, to pave way for a possible

 future different type class instantiation for polynomials over factorial

 rings. INCOMPATIBILITY.

 * Session HOL-Library: theory Sublist provides function "prefixes" with

 the following renaming

   prefixeq -> prefix

   prefix -> strict_prefix

   suffixeq -> suffix

   suffix -> strict_suffix

 Added theory of longest common prefixes.

 * Session HOL-Number_Theory: algebraic foundation for primes:

 Generalisation of predicate "prime" and introduction of predicates

 "prime_elem", "irreducible", a "prime_factorization" function, and the

 "factorial_ring" typeclass with instance proofs for nat, int, poly. Some

 theorems now have different names, most notably "prime_def" is now

 "prime_nat_iff". INCOMPATIBILITY.

 * Session Old_Number_Theory has been removed, after porting remaining

 theories.

 * Session HOL-Types_To_Sets provides an experimental extension of

 Higher-Order Logic to allow translation of types to sets.

 *** ML ***

 * Integer.gcd and Integer.lcm use efficient operations from the Poly/ML

 library (notably for big integers). Subtle change of semantics:

 Integer.gcd and Integer.lcm both normalize the sign, results are never

 negative. This coincides with the definitions in HOL/GCD.thy.

 INCOMPATIBILITY.

 * Structure Rat for rational numbers is now an integral part of

 Isabelle/ML, with special notation @int/nat or @int for numerals (an

 abbreviation for antiquotation @{Pure.rat argument}) and ML pretty

 printing. Standard operations on type Rat.rat are provided via ad-hoc

 overloading of + - * / < <= > >= ~ abs. INCOMPATIBILITY, need to

 use + instead of +/ etc. Moreover, exception Rat.DIVZERO has been

 superseded by General.Div.

 * ML antiquotation @{path} is superseded by @{file}, which ensures that

 the argument is a plain file. Minor INCOMPATIBILITY.

 * Antiquotation @{make_string} is available during Pure bootstrap --

 with approximative output quality.

 * Low-level ML system structures (like PolyML and RunCall) are no longer

 exposed to Isabelle/ML user-space. Potential INCOMPATIBILITY.

 * The ML function "ML" provides easy access to run-time compilation.

 This is particularly useful for conditional compilation, without

 requiring separate files.

 * Option ML_exception_debugger controls detailed exception trace via the

 Poly/ML debugger. Relevant ML modules need to be compiled beforehand

 with ML_file_debug, or with ML_file and option ML_debugger enabled. Note

 debugger information requires consirable time and space: main

 Isabelle/HOL with full debugger support may need ML_system_64.

 * Local_Theory.restore has been renamed to Local_Theory.reset to

 emphasize its disruptive impact on the cumulative context, notably the

 scope of 'private' or 'qualified' names. Note that Local_Theory.reset is

 only appropriate when targets are managed, e.g. starting from a global

 theory and returning to it. Regular definitional packages should use

 balanced blocks of Local_Theory.open_target versus

 Local_Theory.close_target instead. Rare INCOMPATIBILITY.

 * Structure TimeLimit (originally from the SML/NJ library) has been

 replaced by structure Timeout, with slightly different signature.

 INCOMPATIBILITY.

 * Discontinued cd and pwd operations, which are not well-defined in a

 multi-threaded environment. Note that files are usually located

 relatively to the master directory of a theory (see also

 File.full_path). Potential INCOMPATIBILITY.

 * Binding.empty_atts supersedes Thm.empty_binding and

 Attrib.empty_binding. Minor INCOMPATIBILITY.

 *** System ***

 * SML/NJ and old versions of Poly/ML are no longer supported.

 * Poly/ML heaps now follow the hierarchy of sessions, and thus require

 much less disk space.

 * The Isabelle ML process is now managed directly by Isabelle/Scala, and

 shell scripts merely provide optional command-line access. In

 particular:

   . Scala module ML_Process to connect to the raw ML process,

     with interaction via stdin/stdout/stderr or in batch mode;

   . command-line tool "isabelle console" as interactive wrapper;

   . command-line tool "isabelle process" as batch mode wrapper.

 * The executable "isabelle_process" has been discontinued. Tools and

 prover front-ends should use ML_Process or Isabelle_Process in

 Isabelle/Scala. INCOMPATIBILITY.

 * New command-line tool "isabelle process" supports ML evaluation of

 literal expressions (option -e) or files (option -f) in the context of a

 given heap image. Errors lead to premature exit of the ML process with

 return code 1.

 * The command-line tool "isabelle build" supports option -N for cyclic

 shuffling of NUMA CPU nodes. This may help performance tuning on Linux

 servers with separate CPU/memory modules.

 * System option "threads" (for the size of the Isabelle/ML thread farm)

 is also passed to the underlying ML runtime system as --gcthreads,

 unless there is already a default provided via ML_OPTIONS settings.

 * System option "checkpoint" helps to fine-tune the global heap space

 management of isabelle build. This is relevant for big sessions that may

 exhaust the small 32-bit address space of the ML process (which is used

 by default).

 * System option "profiling" specifies the mode for global ML profiling

 in "isabelle build". Possible values are "time", "allocations". The

 command-line tool "isabelle profiling_report" helps to digest the

 resulting log files.

 * System option "ML_process_policy" specifies an optional command prefix

 for the underlying ML process, e.g. to control CPU affinity on

 multiprocessor systems. The "isabelle jedit" tool allows to override the

 implicit default via option -p.

 * Command-line tool "isabelle console" provides option -r to help to

 bootstrapping Isabelle/Pure interactively.

 * Command-line tool "isabelle yxml" has been discontinued.

 INCOMPATIBILITY, use operations from the modules "XML" and "YXML" in

 Isabelle/ML or Isabelle/Scala.

 * Many Isabelle tools that require a Java runtime system refer to the

 settings ISABELLE_TOOL_JAVA_OPTIONS32 / ISABELLE_TOOL_JAVA_OPTIONS64,

 depending on the underlying platform. The settings for "isabelle build"

 ISABELLE_BUILD_JAVA_OPTIONS32 / ISABELLE_BUILD_JAVA_OPTIONS64 have been

 discontinued. Potential INCOMPATIBILITY.

 * The Isabelle system environment always ensures that the main

 executables are found within the shell search $PATH: "isabelle" and

 "isabelle_scala_script".

 * Isabelle tools may consist of .scala files: the Scala compiler is

 invoked on the spot. The source needs to define some object that extends

 Isabelle_Tool.Body.

 * File.bash_string, File.bash_path etc. represent Isabelle/ML and

 Isabelle/Scala strings authentically within GNU bash. This is useful to

 produce robust shell scripts under program control, without worrying

 about spaces or special characters. Note that user output works via

 Path.print (ML) or Path.toString (Scala). INCOMPATIBILITY, the old (and

 less versatile) operations File.shell_quote, File.shell_path etc. have

 been discontinued.

 * The isabelle_java executable allows to run a Java process within the

 name space of Java and Scala components that are bundled with Isabelle,

 but without the Isabelle settings environment.

 * Isabelle/Scala: the SSH module supports ssh and sftp connections, for

 remote command-execution and file-system access. This resembles

 operations from module File and Isabelle_System to some extent. Note

 that Path specifications need to be resolved remotely via

 ssh.remote_path instead of File.standard_path: the implicit process

 environment is different, Isabelle settings are not available remotely.

 * Isabelle/Scala: the Mercurial module supports repositories via the

 regular hg command-line interface. The repositroy clone and working

 directory may reside on a local or remote file-system (via ssh

 connection).

 New in Isabelle2016 (February 2016)

 -----------------------------------

 *** General ***

 * Eisbach is now based on Pure instead of HOL. Objects-logics may import

 either the theory ~~/src/HOL/Eisbach/Eisbach (for HOL etc.) or

 ~~/src/HOL/Eisbach/Eisbach_Old_Appl_Syntax (for FOL, ZF etc.). Note that

 the HOL-Eisbach session located in ~~/src/HOL/Eisbach/ contains further

 examples that do require HOL.

 * Better resource usage on all platforms (Linux, Windows, Mac OS X) for

 both Isabelle/ML and Isabelle/Scala.  Slightly reduced heap space usage.

 * Former "xsymbols" syntax with Isabelle symbols is used by default,

 without any special print mode. Important ASCII replacement syntax

 remains available under print mode "ASCII", but less important syntax

 has been removed (see below).

 * Support for more arrow symbols, with rendering in LaTeX and Isabelle

 fonts: \<Lleftarrow> \<Rrightarrow> \<longlongleftarrow> \<longlongrightarrow> \<longlonglongleftarrow> \<longlonglongrightarrow>.

 * Special notation \<struct> for the first implicit 'structure' in the

 context has been discontinued. Rare INCOMPATIBILITY, use explicit

 structure name instead, notably in indexed notation with block-subscript

 (e.g. \<odot>\<^bsub>A\<^esub>).

 * The glyph for \<diamond> in the IsabelleText font now corresponds better to its

 counterpart \<box> as quantifier-like symbol. A small diamond is available as

 \<diamondop>; the old symbol \<struct> loses this rendering and any special

 meaning.

 * Syntax for formal comments "-- text" now also supports the symbolic

 form "\<comment> text". Command-line tool "isabelle update_cartouches -c" helps

 to update old sources.

 * Toplevel theorem statements have been simplified as follows:

   theorems             ~>  lemmas