
diff -r 4b0563bc4b03 -r 7d8949da7d99 Quot/Nominal/Nominal2_Supp.thy
--- a/Quot/Nominal/Nominal2_Supp.thy	Wed Feb 24 17:32:43 2010 +0100
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,375 +0,0 @@
-(*  Title:      Nominal2_Supp
-    Authors:    Brian Huffman, Christian Urban
-
-    Supplementary Lemmas and Definitions for 
-    Nominal Isabelle. 
-*)
-theory Nominal2_Supp
-imports Nominal2_Base Nominal2_Eqvt Nominal2_Atoms
-begin
-
-
-section {* Fresh-Star *}
-
-text {* The fresh-star generalisation of fresh is used in strong
-  induction principles. *}
-
-definition 
-  fresh_star :: "atom set \<Rightarrow> 'a::pt \<Rightarrow> bool" ("_ \<sharp>* _" [80,80] 80)
-where 
-  "xs \<sharp>* c \<equiv> \<forall>x \<in> xs. x \<sharp> c"
-
-lemma fresh_star_prod:
-  fixes xs::"atom set"
-  shows "xs \<sharp>* (a, b) = (xs \<sharp>* a \<and> xs \<sharp>* b)"
-  by (auto simp add: fresh_star_def fresh_Pair)
-
-lemma fresh_star_union:
-  shows "(xs \<union> ys) \<sharp>* c = (xs \<sharp>* c \<and> ys \<sharp>* c)"
-  by (auto simp add: fresh_star_def)
-
-lemma fresh_star_insert:
-  shows "(insert x ys) \<sharp>* c = (x \<sharp> c \<and> ys \<sharp>* c)"
-  by (auto simp add: fresh_star_def)
-
-lemma fresh_star_Un_elim:
-  "((S \<union> T) \<sharp>* c \<Longrightarrow> PROP C) \<equiv> (S \<sharp>* c \<Longrightarrow> T \<sharp>* c \<Longrightarrow> PROP C)"
-  unfolding fresh_star_def
-  apply(rule)
-  apply(erule meta_mp)
-  apply(auto)
-  done
-
-lemma fresh_star_insert_elim:
-  "(insert x S \<sharp>* c \<Longrightarrow> PROP C) \<equiv> (x \<sharp> c \<Longrightarrow> S \<sharp>* c \<Longrightarrow> PROP C)"
-  unfolding fresh_star_def
-  by rule (simp_all add: fresh_star_def)
-
-lemma fresh_star_empty_elim:
-  "({} \<sharp>* c \<Longrightarrow> PROP C) \<equiv> PROP C"
-  by (simp add: fresh_star_def)
-
-lemma fresh_star_unit_elim: 
-  shows "(a \<sharp>* () \<Longrightarrow> PROP C) \<equiv> PROP C"
-  by (simp add: fresh_star_def fresh_unit) 
-
-lemma fresh_star_prod_elim: 
-  shows "(a \<sharp>* (x, y) \<Longrightarrow> PROP C) \<equiv> (a \<sharp>* x \<Longrightarrow> a \<sharp>* y \<Longrightarrow> PROP C)"
-  by (rule, simp_all add: fresh_star_prod)
-
-
-section {* Avoiding of atom sets *}
-
-text {* 
-  For every set of atoms, there is another set of atoms
-  avoiding a finitely supported c and there is a permutation
-  which 'translates' between both sets.
-*}
-
-lemma at_set_avoiding_aux:
-  fixes Xs::"atom set"
-  and   As::"atom set"
-  assumes b: "Xs \<subseteq> As"
-  and     c: "finite As"
-  shows "\<exists>p. (p \<bullet> Xs) \<inter> As = {} \<and> (supp p) \<subseteq> (Xs \<union> (p \<bullet> Xs))"
-proof -
-  from b c have "finite Xs" by (rule finite_subset)
-  then show ?thesis using b
-  proof (induct rule: finite_subset_induct)
-    case empty
-    have "0 \<bullet> {} \<inter> As = {}" by simp
-    moreover
-    have "supp (0::perm) \<subseteq> {} \<union> 0 \<bullet> {}" by (simp add: supp_zero_perm)
-    ultimately show ?case by blast
-  next
-    case (insert x Xs)
-    then obtain p where
-      p1: "(p \<bullet> Xs) \<inter> As = {}" and 
-      p2: "supp p \<subseteq> (Xs \<union> (p \<bullet> Xs))" by blast
-    from `x \<in> As` p1 have "x \<notin> p \<bullet> Xs" by fast
-    with `x \<notin> Xs` p2 have "x \<notin> supp p" by fast
-    hence px: "p \<bullet> x = x" unfolding supp_perm by simp
-    have "finite (As \<union> p \<bullet> Xs)"
-      using `finite As` `finite Xs`
-      by (simp add: permute_set_eq_image)
-    then obtain y where "y \<notin> (As \<union> p \<bullet> Xs)" "sort_of y = sort_of x"
-      by (rule obtain_atom)
-    hence y: "y \<notin> As" "y \<notin> p \<bullet> Xs" "sort_of y = sort_of x"
-      by simp_all
-    let ?q = "(x \<rightleftharpoons> y) + p"
-    have q: "?q \<bullet> insert x Xs = insert y (p \<bullet> Xs)"
-      unfolding insert_eqvt
-      using `p \<bullet> x = x` `sort_of y = sort_of x`
-      using `x \<notin> p \<bullet> Xs` `y \<notin> p \<bullet> Xs`
-      by (simp add: swap_atom swap_set_not_in)
-    have "?q \<bullet> insert x Xs \<inter> As = {}"
-      using `y \<notin> As` `p \<bullet> Xs \<inter> As = {}`
-      unfolding q by simp
-    moreover
-    have "supp ?q \<subseteq> insert x Xs \<union> ?q \<bullet> insert x Xs"
-      using p2 unfolding q
-      apply (intro subset_trans [OF supp_plus_perm])
-      apply (auto simp add: supp_swap)
-      done
-    ultimately show ?case by blast
-  qed
-qed
-
-lemma at_set_avoiding:
-  assumes a: "finite Xs"
-  and     b: "finite (supp c)"
-  obtains p::"perm" where "(p \<bullet> Xs)\<sharp>*c" and "(supp p) \<subseteq> (Xs \<union> (p \<bullet> Xs))"
-  using a b at_set_avoiding_aux [where Xs="Xs" and As="Xs \<union> supp c"]
-  unfolding fresh_star_def fresh_def by blast
-
-
-section {* The freshness lemma according to Andrew Pitts *}
-
-lemma fresh_conv_MOST: 
-  shows "a \<sharp> x \<longleftrightarrow> (MOST b. (a \<rightleftharpoons> b) \<bullet> x = x)"
-  unfolding fresh_def supp_def MOST_iff_cofinite by simp
-
-lemma fresh_apply:
-  assumes "a \<sharp> f" and "a \<sharp> x" 
-  shows "a \<sharp> f x"
-  using assms unfolding fresh_conv_MOST
-  unfolding permute_fun_app_eq [where f=f]
-  by (elim MOST_rev_mp, simp)
-
-lemma freshness_lemma:
-  fixes h :: "'a::at \<Rightarrow> 'b::pt"
-  assumes a: "\<exists>a. atom a \<sharp> (h, h a)"
-  shows  "\<exists>x. \<forall>a. atom a \<sharp> h \<longrightarrow> h a = x"
-proof -
-  from a obtain b where a1: "atom b \<sharp> h" and a2: "atom b \<sharp> h b"
-    by (auto simp add: fresh_Pair)
-  show "\<exists>x. \<forall>a. atom a \<sharp> h \<longrightarrow> h a = x"
-  proof (intro exI allI impI)
-    fix a :: 'a
-    assume a3: "atom a \<sharp> h"
-    show "h a = h b"
-    proof (cases "a = b")
-      assume "a = b"
-      thus "h a = h b" by simp
-    next
-      assume "a \<noteq> b"
-      hence "atom a \<sharp> b" by (simp add: fresh_at_base)
-      with a3 have "atom a \<sharp> h b" by (rule fresh_apply)
-      with a2 have d1: "(atom b \<rightleftharpoons> atom a) \<bullet> (h b) = (h b)"
-        by (rule swap_fresh_fresh)
-      from a1 a3 have d2: "(atom b \<rightleftharpoons> atom a) \<bullet> h = h"
-        by (rule swap_fresh_fresh)
-      from d1 have "h b = (atom b \<rightleftharpoons> atom a) \<bullet> (h b)" by simp
-      also have "\<dots> = ((atom b \<rightleftharpoons> atom a) \<bullet> h) ((atom b \<rightleftharpoons> atom a) \<bullet> b)"
-        by (rule permute_fun_app_eq)
-      also have "\<dots> = h a"
-        using d2 by simp
-      finally show "h a = h b"  by simp
-    qed
-  qed
-qed
-
-lemma freshness_lemma_unique:
-  fixes h :: "'a::at \<Rightarrow> 'b::pt"
-  assumes a: "\<exists>a. atom a \<sharp> (h, h a)"
-  shows "\<exists>!x. \<forall>a. atom a \<sharp> h \<longrightarrow> h a = x"
-proof (rule ex_ex1I)
-  from a show "\<exists>x. \<forall>a. atom a \<sharp> h \<longrightarrow> h a = x"
-    by (rule freshness_lemma)
-next
-  fix x y
-  assume x: "\<forall>a. atom a \<sharp> h \<longrightarrow> h a = x"
-  assume y: "\<forall>a. atom a \<sharp> h \<longrightarrow> h a = y"
-  from a x y show "x = y"
-    by (auto simp add: fresh_Pair)
-qed
-
-text {* packaging the freshness lemma into a function *}
-
-definition
-  fresh_fun :: "('a::at \<Rightarrow> 'b::pt) \<Rightarrow> 'b"
-where
-  "fresh_fun h = (THE x. \<forall>a. atom a \<sharp> h \<longrightarrow> h a = x)"
-
-lemma fresh_fun_app:
-  fixes h :: "'a::at \<Rightarrow> 'b::pt"
-  assumes a: "\<exists>a. atom a \<sharp> (h, h a)"
-  assumes b: "atom a \<sharp> h"
-  shows "fresh_fun h = h a"
-unfolding fresh_fun_def
-proof (rule the_equality)
-  show "\<forall>a'. atom a' \<sharp> h \<longrightarrow> h a' = h a"
-  proof (intro strip)
-    fix a':: 'a
-    assume c: "atom a' \<sharp> h"
-    from a have "\<exists>x. \<forall>a. atom a \<sharp> h \<longrightarrow> h a = x" by (rule freshness_lemma)
-    with b c show "h a' = h a" by auto
-  qed
-next
-  fix fr :: 'b
-  assume "\<forall>a. atom a \<sharp> h \<longrightarrow> h a = fr"
-  with b show "fr = h a" by auto
-qed
-
-lemma fresh_fun_app':
-  fixes h :: "'a::at \<Rightarrow> 'b::pt"
-  assumes a: "atom a \<sharp> h" "atom a \<sharp> h a"
-  shows "fresh_fun h = h a"
-  apply (rule fresh_fun_app)
-  apply (auto simp add: fresh_Pair intro: a)
-  done
-
-lemma fresh_fun_eqvt:
-  fixes h :: "'a::at \<Rightarrow> 'b::pt"
-  assumes a: "\<exists>a. atom a \<sharp> (h, h a)"
-  shows "p \<bullet> (fresh_fun h) = fresh_fun (p \<bullet> h)"
-  using a
-  apply (clarsimp simp add: fresh_Pair)
-  apply (subst fresh_fun_app', assumption+)
-  apply (drule fresh_permute_iff [where p=p, THEN iffD2])
-  apply (drule fresh_permute_iff [where p=p, THEN iffD2])
-  apply (simp add: atom_eqvt permute_fun_app_eq [where f=h])
-  apply (erule (1) fresh_fun_app' [symmetric])
-  done
-
-lemma fresh_fun_supports:
-  fixes h :: "'a::at \<Rightarrow> 'b::pt"
-  assumes a: "\<exists>a. atom a \<sharp> (h, h a)"
-  shows "(supp h) supports (fresh_fun h)"
-  apply (simp add: supports_def fresh_def [symmetric])
-  apply (simp add: fresh_fun_eqvt [OF a] swap_fresh_fresh)
-  done
-
-notation fresh_fun (binder "FRESH " 10)
-
-lemma FRESH_f_iff:
-  fixes P :: "'a::at \<Rightarrow> 'b::pure"
-  fixes f :: "'b \<Rightarrow> 'c::pure"
-  assumes P: "finite (supp P)"
-  shows "(FRESH x. f (P x)) = f (FRESH x. P x)"
-proof -
-  obtain a::'a where "atom a \<notin> supp P"
-    using P by (rule obtain_at_base)
-  hence "atom a \<sharp> P"
-    by (simp add: fresh_def)
-  show "(FRESH x. f (P x)) = f (FRESH x. P x)"
-    apply (subst fresh_fun_app' [where a=a, OF _ pure_fresh])
-    apply (cut_tac `atom a \<sharp> P`)
-    apply (simp add: fresh_conv_MOST)
-    apply (elim MOST_rev_mp, rule MOST_I, clarify)
-    apply (simp add: permute_fun_def permute_pure expand_fun_eq)
-    apply (subst fresh_fun_app' [where a=a, OF `atom a \<sharp> P` pure_fresh])
-    apply (rule refl)
-    done
-qed
-
-lemma FRESH_binop_iff:
-  fixes P :: "'a::at \<Rightarrow> 'b::pure"
-  fixes Q :: "'a::at \<Rightarrow> 'c::pure"
-  fixes binop :: "'b \<Rightarrow> 'c \<Rightarrow> 'd::pure"
-  assumes P: "finite (supp P)" 
-  and     Q: "finite (supp Q)"
-  shows "(FRESH x. binop (P x) (Q x)) = binop (FRESH x. P x) (FRESH x. Q x)"
-proof -
-  from assms have "finite (supp P \<union> supp Q)" by simp
-  then obtain a::'a where "atom a \<notin> (supp P \<union> supp Q)"
-    by (rule obtain_at_base)
-  hence "atom a \<sharp> P" and "atom a \<sharp> Q"
-    by (simp_all add: fresh_def)
-  show ?thesis
-    apply (subst fresh_fun_app' [where a=a, OF _ pure_fresh])
-    apply (cut_tac `atom a \<sharp> P` `atom a \<sharp> Q`)
-    apply (simp add: fresh_conv_MOST)
-    apply (elim MOST_rev_mp, rule MOST_I, clarify)
-    apply (simp add: permute_fun_def permute_pure expand_fun_eq)
-    apply (subst fresh_fun_app' [where a=a, OF `atom a \<sharp> P` pure_fresh])
-    apply (subst fresh_fun_app' [where a=a, OF `atom a \<sharp> Q` pure_fresh])
-    apply (rule refl)
-    done
-qed
-
-lemma FRESH_conj_iff:
-  fixes P Q :: "'a::at \<Rightarrow> bool"
-  assumes P: "finite (supp P)" and Q: "finite (supp Q)"
-  shows "(FRESH x. P x \<and> Q x) \<longleftrightarrow> (FRESH x. P x) \<and> (FRESH x. Q x)"
-using P Q by (rule FRESH_binop_iff)
-
-lemma FRESH_disj_iff:
-  fixes P Q :: "'a::at \<Rightarrow> bool"
-  assumes P: "finite (supp P)" and Q: "finite (supp Q)"
-  shows "(FRESH x. P x \<or> Q x) \<longleftrightarrow> (FRESH x. P x) \<or> (FRESH x. Q x)"
-using P Q by (rule FRESH_binop_iff)
-
-
-section {* An example of a function without finite support *}
-
-primrec
-  nat_of :: "atom \<Rightarrow> nat"
-where
-  "nat_of (Atom s n) = n"
-
-lemma atom_eq_iff:
-  fixes a b :: atom
-  shows "a = b \<longleftrightarrow> sort_of a = sort_of b \<and> nat_of a = nat_of b"
-  by (induct a, induct b, simp)
-
-lemma not_fresh_nat_of:
-  shows "\<not> a \<sharp> nat_of"
-unfolding fresh_def supp_def
-proof (clarsimp)
-  assume "finite {b. (a \<rightleftharpoons> b) \<bullet> nat_of \<noteq> nat_of}"
-  hence "finite ({a} \<union> {b. (a \<rightleftharpoons> b) \<bullet> nat_of \<noteq> nat_of})"
-    by simp
-  then obtain b where
-    b1: "b \<noteq> a" and
-    b2: "sort_of b = sort_of a" and
-    b3: "(a \<rightleftharpoons> b) \<bullet> nat_of = nat_of"
-    by (rule obtain_atom) auto
-  have "nat_of a = (a \<rightleftharpoons> b) \<bullet> (nat_of a)" by (simp add: permute_nat_def)
-  also have "\<dots> = ((a \<rightleftharpoons> b) \<bullet> nat_of) ((a \<rightleftharpoons> b) \<bullet> a)" by (simp add: permute_fun_app_eq)
-  also have "\<dots> = nat_of ((a \<rightleftharpoons> b) \<bullet> a)" using b3 by simp
-  also have "\<dots> = nat_of b" using b2 by simp
-  finally have "nat_of a = nat_of b" by simp
-  with b2 have "a = b" by (simp add: atom_eq_iff)
-  with b1 show "False" by simp
-qed
-
-lemma supp_nat_of:
-  shows "supp nat_of = UNIV"
-  using not_fresh_nat_of [unfolded fresh_def] by auto
-
-
-section {* Support for sets of atoms *}
-
-lemma supp_finite_atom_set:
-  fixes S::"atom set"
-  assumes "finite S"
-  shows "supp S = S"
-  apply(rule finite_supp_unique)
-  apply(simp add: supports_def)
-  apply(simp add: swap_set_not_in)
-  apply(rule assms)
-  apply(simp add: swap_set_in)
-done
-
-
-(*
-lemma supp_infinite:
-  fixes S::"atom set"
-  assumes asm: "finite (UNIV - S)"
-  shows "(supp S) = (UNIV - S)"
-apply(rule finite_supp_unique)
-apply(auto simp add: supports_def permute_set_eq swap_atom)[1]
-apply(rule asm)
-apply(auto simp add: permute_set_eq swap_atom)[1]
-done
-
-lemma supp_infinite_coinfinite:
-  fixes S::"atom set"
-  assumes asm1: "infinite S"
-  and     asm2: "infinite (UNIV-S)"
-  shows "(supp S) = (UNIV::atom set)"
-*)
-
-
-end
\ No newline at end of file




