src/HOL/Lifting_Set.thy
 author desharna Thu, 29 Oct 2020 16:07:41 +0100 changeset 72518 4be6ae020fc4 parent 70927 cc204e10385c permissions -rw-r--r--
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(*  Title:      HOL/Lifting_Set.thy
Author:     Brian Huffman and Ondrej Kuncar
*)

section \<open>Setup for Lifting/Transfer for the set type\<close>

theory Lifting_Set
imports Lifting
begin

subsection \<open>Relator and predicator properties\<close>

lemma rel_setD1: "\<lbrakk> rel_set R A B; x \<in> A \<rbrakk> \<Longrightarrow> \<exists>y \<in> B. R x y"
and rel_setD2: "\<lbrakk> rel_set R A B; y \<in> B \<rbrakk> \<Longrightarrow> \<exists>x \<in> A. R x y"

lemma rel_set_conversep [simp]: "rel_set A\<inverse>\<inverse> = (rel_set A)\<inverse>\<inverse>"
unfolding rel_set_def by auto

lemma rel_set_eq [relator_eq]: "rel_set (=) = (=)"
unfolding rel_set_def fun_eq_iff by auto

lemma rel_set_mono[relator_mono]:
assumes "A \<le> B"
shows "rel_set A \<le> rel_set B"
using assms unfolding rel_set_def by blast

lemma rel_set_OO[relator_distr]: "rel_set R OO rel_set S = rel_set (R OO S)"
apply (rule sym)
apply (intro ext)
subgoal for X Z
apply (rule iffI)
apply (rule relcomppI [where b="{y. (\<exists>x\<in>X. R x y) \<and> (\<exists>z\<in>Z. S y z)}"])
done
done

lemma Domainp_set[relator_domain]:
"Domainp (rel_set T) = (\<lambda>A. Ball A (Domainp T))"
unfolding rel_set_def Domainp_iff[abs_def]
apply (intro ext)
apply (rule iffI)
apply blast
subgoal for A by (rule exI [where x="{y. \<exists>x\<in>A. T x y}"]) fast
done

lemma left_total_rel_set[transfer_rule]:
"left_total A \<Longrightarrow> left_total (rel_set A)"
unfolding left_total_def rel_set_def
apply safe
subgoal for X by (rule exI [where x="{y. \<exists>x\<in>X. A x y}"]) fast
done

lemma left_unique_rel_set[transfer_rule]:
"left_unique A \<Longrightarrow> left_unique (rel_set A)"
unfolding left_unique_def rel_set_def
by fast

lemma right_total_rel_set [transfer_rule]:
"right_total A \<Longrightarrow> right_total (rel_set A)"
using left_total_rel_set[of "A\<inverse>\<inverse>"] by simp

lemma right_unique_rel_set [transfer_rule]:
"right_unique A \<Longrightarrow> right_unique (rel_set A)"
unfolding right_unique_def rel_set_def by fast

lemma bi_total_rel_set [transfer_rule]:
"bi_total A \<Longrightarrow> bi_total (rel_set A)"

lemma bi_unique_rel_set [transfer_rule]:
"bi_unique A \<Longrightarrow> bi_unique (rel_set A)"
unfolding bi_unique_def rel_set_def by fast

lemma set_relator_eq_onp [relator_eq_onp]:
"rel_set (eq_onp P) = eq_onp (\<lambda>A. Ball A P)"
unfolding fun_eq_iff rel_set_def eq_onp_def Ball_def by fast

lemma bi_unique_rel_set_lemma:
assumes "bi_unique R" and "rel_set R X Y"
obtains f where "Y = image f X" and "inj_on f X" and "\<forall>x\<in>X. R x (f x)"
proof
define f where "f x = (THE y. R x y)" for x
{ fix x assume "x \<in> X"
with \<open>rel_set R X Y\<close> \<open>bi_unique R\<close> have "R x (f x)"
by (simp add: bi_unique_def rel_set_def f_def) (metis theI)
with assms \<open>x \<in> X\<close>
have  "R x (f x)" "\<forall>x'\<in>X. R x' (f x) \<longrightarrow> x = x'" "\<forall>y\<in>Y. R x y \<longrightarrow> y = f x" "f x \<in> Y"
by (fastforce simp add: bi_unique_def rel_set_def)+ }
note * = this
moreover
{ fix y assume "y \<in> Y"
with \<open>rel_set R X Y\<close> *(3) \<open>y \<in> Y\<close> have "\<exists>x\<in>X. y = f x"
by (fastforce simp: rel_set_def) }
ultimately show "\<forall>x\<in>X. R x (f x)" "Y = image f X" "inj_on f X"
by (auto simp: inj_on_def image_iff)
qed

subsection \<open>Quotient theorem for the Lifting package\<close>

lemma Quotient_set[quot_map]:
assumes "Quotient R Abs Rep T"
shows "Quotient (rel_set R) (image Abs) (image Rep) (rel_set T)"
using assms unfolding Quotient_alt_def4
apply fast
done

subsection \<open>Transfer rules for the Transfer package\<close>

subsubsection \<open>Unconditional transfer rules\<close>

context includes lifting_syntax
begin

lemma empty_transfer [transfer_rule]: "(rel_set A) {} {}"
unfolding rel_set_def by simp

lemma insert_transfer [transfer_rule]:
"(A ===> rel_set A ===> rel_set A) insert insert"
unfolding rel_fun_def rel_set_def by auto

lemma union_transfer [transfer_rule]:
"(rel_set A ===> rel_set A ===> rel_set A) union union"
unfolding rel_fun_def rel_set_def by auto

lemma Union_transfer [transfer_rule]:
"(rel_set (rel_set A) ===> rel_set A) Union Union"
unfolding rel_fun_def rel_set_def by simp fast

lemma image_transfer [transfer_rule]:
"((A ===> B) ===> rel_set A ===> rel_set B) image image"
unfolding rel_fun_def rel_set_def by simp fast

lemma UNION_transfer [transfer_rule]: \<comment> \<open>TODO deletion candidate\<close>
"(rel_set A ===> (A ===> rel_set B) ===> rel_set B) (\<lambda>A f. \<Union>(f ` A)) (\<lambda>A f. \<Union>(f ` A))"
by transfer_prover

lemma Ball_transfer [transfer_rule]:
"(rel_set A ===> (A ===> (=)) ===> (=)) Ball Ball"
unfolding rel_set_def rel_fun_def by fast

lemma Bex_transfer [transfer_rule]:
"(rel_set A ===> (A ===> (=)) ===> (=)) Bex Bex"
unfolding rel_set_def rel_fun_def by fast

lemma Pow_transfer [transfer_rule]:
"(rel_set A ===> rel_set (rel_set A)) Pow Pow"
apply (rule rel_funI)
apply (rule rel_setI)
subgoal for X Y X'
apply (rule rev_bexI [where x="{y\<in>Y. \<exists>x\<in>X'. A x y}"])
apply clarsimp
apply fast
done
subgoal for X Y Y'
apply (rule rev_bexI [where x="{x\<in>X. \<exists>y\<in>Y'. A x y}"])
apply clarsimp
apply fast
done
done

lemma rel_set_transfer [transfer_rule]:
"((A ===> B ===> (=)) ===> rel_set A ===> rel_set B ===> (=)) rel_set rel_set"
unfolding rel_fun_def rel_set_def by fast

lemma bind_transfer [transfer_rule]:
"(rel_set A ===> (A ===> rel_set B) ===> rel_set B) Set.bind Set.bind"
unfolding bind_UNION [abs_def] by transfer_prover

lemma INF_parametric [transfer_rule]: \<comment> \<open>TODO deletion candidate\<close>
"(rel_set A ===> (A ===> HOL.eq) ===> HOL.eq) (\<lambda>A f. Inf (f ` A)) (\<lambda>A f. Inf (f ` A))"
by transfer_prover

lemma SUP_parametric [transfer_rule]: \<comment> \<open>TODO deletion candidate\<close>
"(rel_set R ===> (R ===> HOL.eq) ===> HOL.eq) (\<lambda>A f. Sup (f ` A)) (\<lambda>A f. Sup (f ` A))"
by transfer_prover

subsubsection \<open>Rules requiring bi-unique, bi-total or right-total relations\<close>

lemma member_transfer [transfer_rule]:
assumes "bi_unique A"
shows "(A ===> rel_set A ===> (=)) (\<in>) (\<in>)"
using assms unfolding rel_fun_def rel_set_def bi_unique_def by fast

lemma right_total_Collect_transfer[transfer_rule]:
assumes "right_total A"
shows "((A ===> (=)) ===> rel_set A) (\<lambda>P. Collect (\<lambda>x. P x \<and> Domainp A x)) Collect"
using assms unfolding right_total_def rel_set_def rel_fun_def Domainp_iff by fast

lemma Collect_transfer [transfer_rule]:
assumes "bi_total A"
shows "((A ===> (=)) ===> rel_set A) Collect Collect"
using assms unfolding rel_fun_def rel_set_def bi_total_def by fast

lemma inter_transfer [transfer_rule]:
assumes "bi_unique A"
shows "(rel_set A ===> rel_set A ===> rel_set A) inter inter"
using assms unfolding rel_fun_def rel_set_def bi_unique_def by fast

lemma Diff_transfer [transfer_rule]:
assumes "bi_unique A"
shows "(rel_set A ===> rel_set A ===> rel_set A) (-) (-)"
using assms unfolding rel_fun_def rel_set_def bi_unique_def
unfolding Ball_def Bex_def Diff_eq
by (safe, simp, metis, simp, metis)

lemma subset_transfer [transfer_rule]:
assumes [transfer_rule]: "bi_unique A"
shows "(rel_set A ===> rel_set A ===> (=)) (\<subseteq>) (\<subseteq>)"
unfolding subset_eq [abs_def] by transfer_prover

context
includes lifting_syntax
begin

lemma strict_subset_transfer [transfer_rule]:
assumes [transfer_rule]: "bi_unique A"
shows "(rel_set A ===> rel_set A ===> (=)) (\<subset>) (\<subset>)"
unfolding subset_not_subset_eq by transfer_prover

end

declare right_total_UNIV_transfer[transfer_rule]

lemma UNIV_transfer [transfer_rule]:
assumes "bi_total A"
shows "(rel_set A) UNIV UNIV"
using assms unfolding rel_set_def bi_total_def by simp

lemma right_total_Compl_transfer [transfer_rule]:
assumes [transfer_rule]: "bi_unique A" and [transfer_rule]: "right_total A"
shows "(rel_set A ===> rel_set A) (\<lambda>S. uminus S \<inter> Collect (Domainp A)) uminus"
unfolding Compl_eq [abs_def]
by (subst Collect_conj_eq[symmetric]) transfer_prover

lemma Compl_transfer [transfer_rule]:
assumes [transfer_rule]: "bi_unique A" and [transfer_rule]: "bi_total A"
shows "(rel_set A ===> rel_set A) uminus uminus"
unfolding Compl_eq [abs_def] by transfer_prover

lemma right_total_Inter_transfer [transfer_rule]:
assumes [transfer_rule]: "bi_unique A" and [transfer_rule]: "right_total A"
shows "(rel_set (rel_set A) ===> rel_set A) (\<lambda>S. \<Inter>S \<inter> Collect (Domainp A)) Inter"
unfolding Inter_eq[abs_def]
by (subst Collect_conj_eq[symmetric]) transfer_prover

lemma Inter_transfer [transfer_rule]:
assumes [transfer_rule]: "bi_unique A" and [transfer_rule]: "bi_total A"
shows "(rel_set (rel_set A) ===> rel_set A) Inter Inter"
unfolding Inter_eq [abs_def] by transfer_prover

lemma filter_transfer [transfer_rule]:
assumes [transfer_rule]: "bi_unique A"
shows "((A ===> (=)) ===> rel_set A ===> rel_set A) Set.filter Set.filter"
unfolding Set.filter_def[abs_def] rel_fun_def rel_set_def by blast

lemma finite_transfer [transfer_rule]:
"bi_unique A \<Longrightarrow> (rel_set A ===> (=)) finite finite"
by (rule rel_funI, erule (1) bi_unique_rel_set_lemma)
(auto dest: finite_imageD)

lemma card_transfer [transfer_rule]:
"bi_unique A \<Longrightarrow> (rel_set A ===> (=)) card card"
by (rule rel_funI, erule (1) bi_unique_rel_set_lemma)

context
includes lifting_syntax
begin

lemma vimage_right_total_transfer[transfer_rule]:
assumes [transfer_rule]: "bi_unique B" "right_total A"
shows "((A ===> B) ===> rel_set B ===> rel_set A) (\<lambda>f X. f -` X \<inter> Collect (Domainp A)) vimage"
proof -
let ?vimage = "(\<lambda>f B. {x. f x \<in> B \<and> Domainp A x})"
have "((A ===> B) ===> rel_set B ===> rel_set A) ?vimage vimage"
unfolding vimage_def
by transfer_prover
also have "?vimage = (\<lambda>f X. f -` X \<inter> Collect (Domainp A))"
by auto
finally show ?thesis .
qed

end

lemma vimage_parametric [transfer_rule]:
assumes [transfer_rule]: "bi_total A" "bi_unique B"
shows "((A ===> B) ===> rel_set B ===> rel_set A) vimage vimage"
unfolding vimage_def[abs_def] by transfer_prover

lemma Image_parametric [transfer_rule]:
assumes "bi_unique A"
shows "(rel_set (rel_prod A B) ===> rel_set A ===> rel_set B) (``) (``)"
by (intro rel_funI rel_setI)
(force dest: rel_setD1 bi_uniqueDr[OF assms], force dest: rel_setD2 bi_uniqueDl[OF assms])

lemma inj_on_transfer[transfer_rule]:
"((A ===> B) ===> rel_set A ===> (=)) inj_on inj_on"
if [transfer_rule]: "bi_unique A" "bi_unique B"
unfolding inj_on_def
by transfer_prover

end

lemma (in comm_monoid_set) F_parametric [transfer_rule]:
fixes A :: "'b \<Rightarrow> 'c \<Rightarrow> bool"
assumes "bi_unique A"
shows "rel_fun (rel_fun A (=)) (rel_fun (rel_set A) (=)) F F"
proof (rule rel_funI)+
fix f :: "'b \<Rightarrow> 'a" and g S T
assume "rel_fun A (=) f g" "rel_set A S T"
with \<open>bi_unique A\<close> obtain i where "bij_betw i S T" "\<And>x. x \<in> S \<Longrightarrow> f x = g (i x)"
by (auto elim: bi_unique_rel_set_lemma simp: rel_fun_def bij_betw_def)
then show "F f S = F g T"