(* ID:         $Id$ *)

theory Examples = Main:

ML "reset eta_contract"

ML "Pretty.setmargin 64"

text{*membership, intersection *}

text{*difference and empty set*}

text{*complement, union and universal set*}

lemma "(x \<in> A \<inter> B) = (x \<in> A \<and> x \<in> B)"

by blast

text{*

@{thm[display] IntI[no_vars]}

\rulename{IntI}

@{thm[display] IntD1[no_vars]}

\rulename{IntD1}

@{thm[display] IntD2[no_vars]}

\rulename{IntD2}

*}

lemma "(x \<in> -A) = (x \<notin> A)"

by blast

text{*

@{thm[display] Compl_iff[no_vars]}

\rulename{Compl_iff}

*}

lemma "- (A \<union> B) = -A \<inter> -B"

by blast

text{*

@{thm[display] Compl_Un[no_vars]}

\rulename{Compl_Un}

*}

lemma "A-A = {}"

by blast

text{*

@{thm[display] Diff_disjoint[no_vars]}

\rulename{Diff_disjoint}

*}

lemma "A \<union> -A = UNIV"

by blast

text{*

@{thm[display] Compl_partition[no_vars]}

\rulename{Compl_partition}

*}

text{*subset relation*}

text{*

@{thm[display] subsetI[no_vars]}

\rulename{subsetI}

@{thm[display] subsetD[no_vars]}

\rulename{subsetD}

*}

lemma "((A \<union> B) \<subseteq> C) = (A \<subseteq> C \<and> B \<subseteq> C)"

by blast

text{*

@{thm[display] Un_subset_iff[no_vars]}

\rulename{Un_subset_iff}

*}

lemma "(A \<subseteq> -B) = (B \<subseteq> -A)"

by blast

lemma "(A <= -B) = (B <= -A)"

  oops

text{*ASCII version: blast fails because of overloading because

 it doesn't have to be sets*}

lemma "((A:: 'a set) <= -B) = (B <= -A)"

by blast

text{*A type constraint lets it work*}

text{*An issue here: how do we discuss the distinction between ASCII and

X-symbol notation?  Here the latter disambiguates.*}

text{*

set extensionality

@{thm[display] set_ext[no_vars]}

\rulename{set_ext}

@{thm[display] equalityI[no_vars]}

\rulename{equalityI}

@{thm[display] equalityE[no_vars]}

\rulename{equalityE}

*}

text{*finite sets: insertion and membership relation*}

text{*finite set notation*}

lemma "insert x A = {x} \<union> A"

by blast

text{*

@{thm[display] insert_is_Un[no_vars]}

\rulename{insert_is_Un}

*}

lemma "{a,b} \<union> {c,d} = {a,b,c,d}"

by blast

lemma "{a,b} \<inter> {b,c} = {b}"

apply auto

oops

text{*fails because it isn't valid*}

lemma "{a,b} \<inter> {b,c} = (if a=c then {a,b} else {b})"

apply simp

by blast

text{*or just force or auto.  blast alone can't handle the if-then-else*}

text{*next: some comprehension examples*}

lemma "(a \<in> {z. P z}) = P a"

by blast

text{*

@{thm[display] mem_Collect_eq[no_vars]}

\rulename{mem_Collect_eq}

*}

lemma "{x. x \<in> A} = A"

by blast

text{*

@{thm[display] Collect_mem_eq[no_vars]}

\rulename{Collect_mem_eq}

*}

lemma "{x. P x \<or> x \<in> A} = {x. P x} \<union> A"

by blast

lemma "{x. P x \<longrightarrow> Q x} = -{x. P x} \<union> {x. Q x}"

by blast

constdefs

  prime   :: "nat set"

    "prime == {p. 1<p & (ALL m. m dvd p --> m=1 | m=p)}"

lemma "{p*q | p q. p\<in>prime \<and> q\<in>prime} = 

       {z. \<exists>p q. z = p*q \<and> p\<in>prime \<and> q\<in>prime}"

by (rule refl)

text{*binders*}

text{*bounded quantifiers*}

lemma "(\<exists>x\<in>A. P x) = (\<exists>x. x\<in>A \<and> P x)"

by blast

text{*

@{thm[display] bexI[no_vars]}

\rulename{bexI}

*}

text{*

@{thm[display] bexE[no_vars]}

\rulename{bexE}

*}

lemma "(\<forall>x\<in>A. P x) = (\<forall>x. x\<in>A \<longrightarrow> P x)"

by blast

text{*

@{thm[display] ballI[no_vars]}

\rulename{ballI}

*}

text{*

@{thm[display] bspec[no_vars]}

\rulename{bspec}

*}

text{*indexed unions and variations*}

lemma "(\<Union>x. B x) = (\<Union>x\<in>UNIV. B x)"

by blast

text{*

@{thm[display] UN_iff[no_vars]}

\rulename{UN_iff}

*}

text{*

@{thm[display] Union_iff[no_vars]}

\rulename{Union_iff}

*}

lemma "(\<Union>x\<in>A. B x) = {y. \<exists>x\<in>A. y \<in> B x}"

by blast

lemma "\<Union>S = (\<Union>x\<in>S. x)"

by blast

text{*

@{thm[display] UN_I[no_vars]}

\rulename{UN_I}

*}

text{*

@{thm[display] UN_E[no_vars]}

\rulename{UN_E}

*}

text{*indexed intersections*}

lemma "(\<Inter>x. B x) = {y. \<forall>x. y \<in> B x}"

by blast

text{*

@{thm[display] INT_iff[no_vars]}

\rulename{INT_iff}

*}

text{*

@{thm[display] Inter_iff[no_vars]}

\rulename{Inter_iff}

*}

text{*mention also card, Pow, etc.*}

text{*

@{thm[display] card_Un_Int[no_vars]}

\rulename{card_Un_Int}

@{thm[display] card_Pow[no_vars]}

\rulename{card_Pow}

@{thm[display] n_subsets[no_vars]}

\rulename{n_subsets}

*}

end