doc-isac/mat-eng.sml
author wneuper <Walther.Neuper@jku.at>
Sun, 31 Dec 2023 09:42:27 +0100
changeset 60787 26037efefd61
parent 60769 0df0759fed26
permissions -rw-r--r--
Doc/Specify_Phase 2: copy finished
     1 (* cut and paste for math.tex
     2 *)
     3 
     4 (*2.2. *)
     5 "a + b * 3";
     6 TermC.parse_test @{context} "a + b * 3";
     7 val term = TermC.parse_test @{context} "a + b * 3";
     8 atomt term;
     9 TermC.atom_trace_detail @{context} term;
    10 
    11 (*2.3. Theories and parsing*)
    12 
    13  > Isac.thy;
    14 val it =
    15    {ProtoPure, CPure, HOL, Set, Typedef, Fun, Product_Type, Lfp, Gfp,
    16      Sum_Type, Relation, Record, Inductive, Transitive_Closure,
    17      Wellfounded_Recursion, NatDef, Nat, NatArith, Divides, Power,
    18      SetInterval, Finite_Set, Equiv, IntDef, Int, Datatype_Universe,
    19      Datatype, Numeral, Bin, IntArith, Wellfounded_Relations, Recdef, IntDiv,
    20      IntPower, NatBin, NatSimprocs, Relation_Power, PreList, List, Map,
    21      Hilbert_Choice, Main, Lubs, PNat, PRat, PReal, RealDef, RealOrd,
    22      RealInt, RealBin, RealArith0, RealArith, RComplete, RealAbs, RealPow,
    23      Ring_and_Field, Complex_Numbers, Real, ListG, Tools, Script, Typefix,
    24      Float, ComplexI, Descript, Atools, Simplify, Poly, Rational, PolyMinus,
    25      Equation, LinEq, Root, RootEq, RatEq, RootRat, RootRatEq, PolyEq, Vect,
    26      Calculus, Trig, LogExp, Diff, DiffApp, Integrate, EqSystem, Biegelinie,
    27      AlgEin, Test, Isac} : Theory.theory
    28 
    29 Group.thy
    30 suche nach '*' Link: http://www.cl.cam.ac.uk/research/hvg/Isabelle/dist/library/HOL/Groups.html
    31 locale semigroup =
    32   fixes f :: "'a => 'a => 'a" (infixl "*" 70)
    33   assumes assoc [ac_simps]: "a * b * c = a * (b * c)"
    34 
    35 > parse;
    36 val it = fn : Theory.theory -> string -> Thm.cterm Library.option
    37 
    38 
    39 
    40 > (*-1-*);
    41 > parse HOL.thy "2^^^3";
    42 *** Inner lexical error at: "^^^3"
    43 val it = None : Thm.cterm Library.option
    44 > (*-2-*);
    45 > parse HOL.thy "d_d x (a + x)";
    46 val it = None : Thm.cterm Library.option
    47 > (*-3-*);
    48 > parse Rational.thy "2^^^3";
    49 val it = Some "2 ^^^ 3" : Thm.cterm Library.option
    50 > (*-4-*);
    51 val Some t4 = parse Rational.thy "d_d x (a + x)";
    52 val t4 = "d_d x (a + x)" : Thm.cterm
    53 > (*-5-*);
    54 val Some t5 = parse Diff.thy  "d_d x (a + x)";
    55 val t5 = "d_d x (a + x)" : Thm.cterm
    56 
    57 
    58 > term_of;
    59 val it = fn : Thm.cterm -> Term.term
    60 > term_of t4;
    61 val it =
    62    Free ("d_d", "[RealDef.real, RealDef.real] => RealDef.real") $
    63          Free ("x", "RealDef.real") $
    64       (Const ("op +", "[RealDef.real, RealDef.real] => RealDef.real") $
    65             Free ("a", "RealDef.real") $ Free ("x", "RealDef.real"))
    66 : Term.term
    67 > term_of t5;
    68 val it =
    69    Const ("Diff.d_d", "[RealDef.real, RealDef.real] => RealDef.real") $
    70          Free ("x", "RealDef.real") $
    71       (Const ("op +", "[RealDef.real, RealDef.real] => RealDef.real") $
    72             Free ("a", "RealDef.real") $ Free ("x", "RealDef.real"))
    73 : Term.term
    74 
    75 > print_depth;
    76 val it = fn : int -> unit
    77 
    78 
    79 
    80 
    81 
    82 > (*-4-*) val thy = Rational.thy;
    83 val thy =
    84    {ProtoPure, CPure, HOL, Set, Typedef, Fun, Product_Type, Lfp, Gfp,
    85      Sum_Type, Relation, Record, Inductive, Transitive_Closure,
    86      Wellfounded_Recursion, NatDef, Nat, NatArith, Divides, Power,
    87      SetInterval, Finite_Set, Equiv, IntDef, Int, Datatype_Universe,
    88      Datatype, Numeral, Bin, IntArith, Wellfounded_Relations, Recdef, IntDiv,
    89      IntPower, NatBin, NatSimprocs, Relation_Power, PreList, List, Map,
    90      Hilbert_Choice, Main, Lubs, PNat, PRat, PReal, RealDef, RealOrd,
    91      RealInt, RealBin, RealArith0, RealArith, RComplete, RealAbs, RealPow,
    92      Ring_and_Field, Complex_Numbers, Real, ListG, Tools, Script, Typefix,
    93      Float, ComplexI, Descript, Atools, Simplify, Poly, Rational}
    94 : Theory.theory
    95 > ((TermC.atom_trace_detail @{context}) o term_of o the o (parse thy)) "d_d x (a + x)";
    96 
    97 ***
    98 *** Free (d_d, [real, real] => real)
    99 *** . Free (x, real)
   100 *** . Const (op +, [real, real] => real)
   101 *** . . Free (a, real)
   102 *** . . Free (x, real)
   103 ***
   104 
   105 val it = () : unit
   106 > (*-5-*) val thy = Diff.thy;
   107 val thy =
   108    {ProtoPure, CPure, HOL, Set, Typedef, Fun, Product_Type, Lfp, Gfp,
   109      Sum_Type, Relation, Record, Inductive, Transitive_Closure,
   110      Wellfounded_Recursion, NatDef, Nat, NatArith, Divides, Power,
   111      SetInterval, Finite_Set, Equiv, IntDef, Int, Datatype_Universe,
   112      Datatype, Numeral, Bin, IntArith, Wellfounded_Relations, Recdef, IntDiv,
   113      IntPower, NatBin, NatSimprocs, Relation_Power, PreList, List, Map,
   114      Hilbert_Choice, Main, Lubs, PNat, PRat, PReal, RealDef, RealOrd,
   115      RealInt, RealBin, RealArith0, RealArith, RComplete, RealAbs, RealPow,
   116      Ring_and_Field, Complex_Numbers, Real, Calculus, Trig, ListG, Tools,
   117      Script, Typefix, Float, ComplexI, Descript, Atools, Simplify, Poly,
   118      Equation, LinEq, Root, RootEq, Rational, RatEq, RootRat, RootRatEq,
   119      PolyEq, LogExp, Diff} : Theory.theory
   120 
   121 > ((TermC.atom_trace_detail @{context}) o term_of o the o (parse thy)) "d_d x (a + x)";
   122 
   123 ***
   124 *** Const (Diff.d_d, [real, real] => real)
   125 *** . Free (x, real)
   126 *** . Const (op +, [real, real] => real)
   127 *** . . Free (a, real)
   128 *** . . Free (x, real)
   129 ***
   130 
   131 val it = () : unit
   132 
   133 
   134 
   135 > print_depth 1;
   136 val it = () : unit
   137 > term_of t4;
   138 val it =
   139    Free ("d_d", "[RealDef.real, RealDef.real] => RealDef.real") $ ... $ ...
   140 : Term.term
   141 
   142 
   143 > print_depth 1;
   144 val it = () : unit
   145 > term_of t5;
   146 val it =
   147    Const ("Diff.d_d", "[RealDef.real, RealDef.real] => RealDef.real") $ ... $
   148       ... : Term.term
   149 
   150 
   151 
   152 -------------------------------------------ALT...
   153 explode it;
   154 	  \footnote{
   155 	  print_depth 9;
   156 	  explode "a + b * 3";
   157 	  }
   158 
   159 (*unschoen*)
   160 
   161 -------------------------------------------ALT...
   162  HOL.thy;
   163  parse;
   164  parse thy "a + b * 3";
   165  val t = (term_of o the) it;
   166  term_of;
   167 
   168 (*2.3. Displaying terms*)
   169  print_depth;
   170  ////Compiler.Control.Print.printDepth;
   171 ? Compiler.Control.Print.printDepth:= 2;
   172  t;
   173  ?Compiler.Control.Print.printDepth:= 6;
   174  t;
   175  ?Compiler.Control.Print.printLength;
   176  ?Compiler.Control.Print.stringDepth;
   177  atomt;
   178  atomt t; 
   179  TermC.atom_trace_detail @{context};
   180  TermC.atom_trace_detail @{context} t;
   181 (*Give it a try: the mathematics knowledge grows*)
   182  parse HOL.thy "2^^^3";
   183  parse HOL.thy "d_d x (a + x)";
   184  ?parse RatArith.thy "#2^^^#3";
   185  ?parse RatArith.thy "d_d x (a + x)";
   186  parse Differentiate.thy "d_d x (a + x)";
   187  ?parse Differentiate.thy "#2^^^#3";
   188 (*don't trust the string representation*)
   189  ?val thy = RatArith.thy;
   190  ((TermC.atom_trace_detail @{context} thy) o term_of o the o (parse thy)) "d_d x (a + x)";
   191  ?val thy = Differentiate.thy;
   192  ((TermC.atom_trace_detail @{context} thy) o term_of o the o (parse thy)) "d_d x (a + x)";
   193 
   194 (*2.4. Converting terms*)
   195  term_of;
   196  the;
   197  val t = (term_of o the o (parse thy)) "a + b * 3";
   198 
   199  sign_of;
   200  cterm_of;
   201  val ct = cterm_of (sign_of thy) t;
   202 
   203  Sign.string_of_term;
   204  Sign.string_of_term (sign_of thy) t;
   205 
   206  string_of_cterm;
   207  string_of_cterm ct;
   208 
   209 (*2.5. Theorems *)
   210  ?theorem' := overwritel (!theorem',
   211   [("diff_const",num_str diff_const)
   212    ]);
   213 
   214 (** 3. Rewriting **)
   215 (*3.1. The arguments for rewriting*)
   216  HOL.thy;
   217  "HOL.thy" : theory';
   218  sqrt_right;
   219  "sqrt_right" : rew_ord;
   220  eval_rls;
   221  "eval_rls" : rls';
   222  diff_sum;
   223  ("diff_sum", "") : thm';
   224 
   225 (*3.2. The functions for rewriting*)
   226  rewrite_;
   227  rewrite;
   228 
   229 > val thy' = "Diff.thy";
   230 val thy' = "Diff.thy" : string
   231 > val ct = "d_d x (a * 3 + b)";
   232 val ct = "d_d x (a * 3 + b)" : string
   233 > val thm = ("diff_sum","");
   234 val thm = ("diff_sum", "") : string * string
   235 > val Some (ct,_) = rewrite_inst thy' "tless_true" "eval_rls" true
   236                      [("bdv","x::real")] thm ct;
   237 val ct = "d_d x (a * 3) + d_d x b" : cterm'
   238 > val thm = ("diff_prod_const","");
   239 val thm = ("diff_prod_const", "") : string * string
   240 > val Some (ct,_) = rewrite_inst thy' "tless_true" "eval_rls" true
   241                      [("bdv","x::real")] thm ct;
   242 val ct = "a * d_d x 3 + d_d x b" : cterm'
   243 
   244 
   245 
   246 > val thy' = "Diff.thy";
   247 val thy' = "Diff.thy" : string
   248 > val ct = "d_d x (a + a * (2 + b))";
   249 val ct = "d_d x (a + a * (2 + b))" : string
   250 > val thm = ("diff_sum","");
   251 val thm = ("diff_sum", "") : string * string
   252 > val Some (ct,_) = rewrite_inst thy' "tless_true" "eval_rls" true
   253                      [("bdv","x::real")] thm ct;
   254 val ct = "d_d x a + d_d x (a * (2 + b))" : cterm'
   255 
   256 > val thm = ("diff_prod_const","");
   257 val thm = ("diff_prod_const", "") : string * string
   258 > val Some (ct,_) = rewrite_inst thy' "tless_true" "eval_rls" true
   259                      [("bdv","x::real")] thm ct;
   260 val ct = "d_d x a + a * d_d x (2 + b)" : cterm'
   261 
   262 
   263 
   264 (*Give it a try: rewriting*)
   265  val thy' = "Diff.thy";
   266  val ct = "d_d x (x ^^^ 2 + 3 * x + 4)";
   267  val thm = ("diff_sum","");
   268  val Some (ct,_) = rewrite_inst thy' "tless_true" "eval_rls" true [("bdv","x::real")] thm ct;
   269  val Some (ct,_) = rewrite_inst thy' "tless_true" "eval_rls" true  [("bdv","x::real")] thm ct;
   270  val thm = ("diff_prod_const","");
   271  val Some (ct,_) = rewrite_inst thy' "tless_true" "eval_rls" true [("bdv","x::real")] thm ct;
   272 (*Give it a try: conditional rewriting*)
   273  val thy' = "Isac.thy";
   274  val ct' = "3 * a + 2 * (a + 1)";
   275  val thm' = ("radd_mult_distrib2","?k * (?m + ?n) = ?k * ?m + ?k * ?n");
   276  (*1*) val Some (ct',_) = rewrite thy' "tless_true" "eval_rls" true thm' ct';
   277  val thm' = ("radd_assoc_RS_sym","?m1 + (?n1 + ?k1) = ?m1 + ?n1 + ?k1");
   278  ?(*2*) val Some (ct',_) = rewrite thy' "tless_true" "eval_rls" true thm' ct';
   279  ?val thm' = ("rcollect_right",
   280      "[| ?l is_const; ?m is_const |] ==> ?l * ?n + ?m * ?n = (?l + ?m) * ?n");
   281  ?(*3*) val Some (ct',_) = rewrite thy' "tless_true" "eval_rls" true thm' ct';
   282  ?(*4*) val Some (ct',_) = calculate thy' "plus" ct';
   283  ?(*5*) val Some (ct',_) = calculate thy' "times" ct';
   284 
   285 (*Give it a try: functional programming*)
   286  val thy' = "InsSort.thy";
   287  val ct = "sort [#1,#3,#2]" : cterm';
   288 
   289  val thm = ("sort_def","");
   290  ?val (ct,_) = the (rewrite thy' "tless_true" "eval_rls" false thm ct);
   291 
   292  val thm = ("foldr_rec","");
   293  ?val (ct,_) = the (rewrite thy' "tless_true" "eval_rls" false thm ct);
   294 
   295  val thm = ("ins_base","");
   296  ?val (ct,_) = the (rewrite thy' "tless_true" "eval_rls" false thm ct);
   297 
   298  val thm = ("foldr_rec","");
   299  ?val (ct,_) = the (rewrite thy' "tless_true" "eval_rls" false thm ct);
   300 
   301  val thm = ("ins_rec","");
   302  ?val (ct,_) = the (rewrite thy' "tless_true" "eval_rls" false thm ct);
   303 
   304  ?val (ct,_) = the (calculate thy' "le" ct);
   305 
   306  val thm = ("if_True","(if True then ?x else ?y) = ?x");
   307  ?val (ct,_) = the (rewrite thy' "tless_true" "eval_rls" false thm ct);
   308 
   309 (*3.3. Variants of rewriting*)
   310  rewrite_inst_;
   311  rewrite_inst;
   312 
   313  rewrite_set_;
   314  rewrite_set;
   315 
   316  rewrite_set_inst_;
   317  rewrite_set_inst;
   318 
   319  toggle;
   320  toggle trace_rewrite;
   321 
   322 (*3.4. Rule sets*)
   323  sym;
   324  rearrange_assoc;
   325 
   326 (*Give it a try: remove parentheses*)
   327  ?val ct = (string_of_cterm o the o (parse RatArith.thy))
   328            "a + (b * (c * d) + e)";
   329  ?rewrite_set "RatArith.thy" "eval_rls" false "rearrange_assoc" ct;
   330 
   331  toggle trace_rewrite;
   332  ?rewrite_set "RatArith.thy" "eval_rls" false "rearrange_assoc" ct;
   333 
   334 (*3.5. Calculate numeric constants*)
   335  calculate;
   336  calculate_;
   337 
   338  ?calc_list;
   339  ?calculate "Isac.thy" "plus" "#1 + #2";
   340  ?calculate "Isac.thy" "times" "#2 * #3";
   341  ?calculate "Isac.thy" "power" "#2 ^^^ #3";
   342  ?calculate "Isac.thy" "cancel_" "#9 // #12";
   343    
   344 
   345 (** 4. Term orders **)
   346 (*4.1. Exmpales for term orders*)
   347  sqrt_right;
   348  tless_true;
   349 
   350  val t1 = (term_of o the o (parse thy)) "(sqrt a) + b";
   351  val t2 = (term_of o the o (parse thy)) "b + (sqrt a)";
   352  ?sqrt_right false SqRoot.thy (t1, t2);
   353  ?sqrt_right false SqRoot.thy (t2, t1);
   354 
   355  val t1 = (term_of o the o (parse thy)) "a + b*(sqrt c) + d";
   356  val t2 = (term_of o the o (parse thy)) "a + (sqrt b)*c + d";
   357  ?sqrt_right true SqRoot.thy (t1, t2);
   358 
   359 (*4.2. Ordered rewriting*)   
   360  ac_plus_times;
   361 
   362 (*Give it a try: polynomial (normal) form*)
   363  val ct' = "#3 * a + b + #2 * a";
   364  val thm' = ("radd_commute","") : thm';
   365  ?val Some (ct',_) = rewrite thy' "tless_true" "eval_rls" true thm' ct';
   366  val thm' = ("rdistr_right_assoc_p","") : thm';
   367  ?val Some (ct',_) = rewrite thy' "tless_true" "eval_rls" true thm' ct';
   368  ?val Some (ct',_) = calculate thy' "plus" ct';
   369 
   370  val ct' = "3 * a + b + 2 * a" : cterm';
   371  val thm' = ("radd_commute","") : thm';
   372  ?val Some (ct',_) = rewrite thy' "tless_true" "eval_rls" true thm' ct';
   373  ?val Some (ct',_) = rewrite thy' "tless_true" "eval_rls" true thm' ct';
   374  ?val Some (ct',_) = rewrite thy' "tless_true" "eval_rls" true thm' ct';
   375 
   376  toggle trace_rewrite;
   377  ?rewrite_set "RatArith.thy" "eval_rls" false "ac_plus_times" ct;
   378 
   379 
   380 (** 5. The hierarchy of problem types **)
   381 (*5.1. The standard-function for 'matching'*)
   382  matches;
   383 
   384  val t = (term_of o the o (parse thy)) "3 * x^^^2 = 1";
   385  val p = (term_of o the o (parse thy)) "a * b^^^2 = c";
   386  atomt p;
   387  mk_Var;
   388  val pat = mk_Var p;
   389  matches thy t pat;
   390 
   391  val t2 = (term_of o the o (parse thy)) "x^^^2 = 1";
   392  matches thy t2 pat;
   393 
   394  val pat2 = (term_of o the o (parse thy)) "?u^^^2 = ?v";
   395  matches thy t2 pat2;
   396 
   397 (*5.2. Accessing the hierarchy*)
   398  show_ptyps;
   399  show_ptyps();
   400  get_pbt;
   401  ?get_pbt ["squareroot", "univariate", "equation"];
   402 
   403  store_pbt;
   404  ?store_pbt
   405     (prep_pbt SqRoot.thy
   406     (["newtype","univariate","equation"],
   407      [("#Given" ,["equality e_","solveFor v_","errorBound err_"]),
   408       ("#Where" ,["contains_root (e_::bool)"]),
   409       ("#Find"  ,["solutions v_i_"])
   410      ],
   411      [("SqRoot.thy","square_equation")]));
   412  show_ptyps();
   413 
   414 (*5.3. Internals of the datastructure*)
   415 (*5.4. Match a problem with a problem type*)
   416  ?val fmz = ["equality (#1 + #2 * x = #0)",
   417  	    "solveFor x",
   418  	    "solutions L"] : fmz;
   419  by_formalise;
   420  ?by_formalise fmz (get_pbt ["univariate","equation"]);
   421  ?by_formalise fmz (get_pbt ["linear","univariate","equation"]);
   422  ?by_formalise fmz (get_pbt ["squareroot","univariate","equation"]);
   423 
   424 (*5.5. Refine a problem specification *)
   425  refine;
   426  ?val fmz = ["equality (sqrt(#9+#4*x)=sqrt x + sqrt(#5+x))",
   427  	    "solveFor x","errorBound (eps=#0)",
   428  	    "solutions L"];
   429  ?refine fmz ["univariate","equation"];
   430 
   431  ?val fmz = ["equality (x+#1=#2)",
   432  	    "solveFor x","errorBound (eps=#0)",
   433  	    "solutions L"];
   434  ?refine fmz ["univariate","equation"];
   435  
   436 
   437 (* 6. Do a calculational proof *)
   438  ?val fmz = ["equality ((x+#1) * (x+#2) = x^^^#2+#8)","solveFor x",
   439  	    "errorBound (eps=#0)","solutions L"];
   440  val spec as (dom, pbt, met) = ("SqRoot.thy",["univariate","equation"],
   441  				("SqRoot.thy","no_met"));
   442  
   443 (*6.1. Initialize the calculation*)
   444  val p = e_pos'; val c = [];
   445  ?val (mID,m) = ("Init_Proof",Init_Proof (fmz, (dom,pbt,met)));
   446  ?val (p,_,f,nxt,_,pt) = me (mID,m) p c EmptyPtree;
   447 
   448  ?Compiler.Control.Print.printDepth:=8;
   449  ?f;
   450  ?Compiler.Control.Print.printDepth:=4;
   451 
   452  ?nxt;
   453  ?val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   454  ?val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   455 
   456 (*6.2. The phase of modeling*)
   457  ?nxt;
   458  ?val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   459  ?val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   460  ?val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   461 
   462  ?Compiler.Control.Print.printDepth:=8;
   463  ?f;
   464  ?Compiler.Control.Print.printDepth:=4;
   465 
   466 (*6.3. The phase of specification*)
   467  ?nxt;
   468  ?val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   469 
   470 
   471  val nxt = ("Specify_Problem",
   472 	    Specify_Problem ["polynomial","univariate","equation"]);
   473  ?val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   474 
   475  val nxt = ("Specify_Problem",
   476 	    Specify_Problem ["linear","univariate","equation"]);
   477  ?val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   478  ?Compiler.Control.Print.printDepth:=8;f;Compiler.Control.Print.printDepth:=4;
   479 
   480  val nxt = ("Refine_Problem",
   481 	    Refine_Problem ["linear","univariate","equation"]);
   482  ?val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   483  ?Compiler.Control.Print.printDepth:=9;f;Compiler.Control.Print.printDepth:=4;
   484 
   485  val nxt = ("Refine_Problem",Refine_Problem ["univariate","equation"]);
   486  ?val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   487  ?Compiler.Control.Print.printDepth:=9;f;Compiler.Control.Print.printDepth:=4;
   488 
   489  ?val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   490  ?val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   491 
   492 (*6.4. The phase of solving*)
   493  nxt;
   494  ?val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   495  val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   496  val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   497 
   498  val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   499  val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   500  val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   501  val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   502  val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   503  val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   504  val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   505  val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   506  val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   507  val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   508  val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   509  val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   510 
   511 (*6.5. The final phase: check the postcondition*)
   512  ?val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   513  val (p,_,f,nxt,_,pt) = me nxt p [1] pt;
   514 
   515 
   516 
   517 
   518 
   519