new example theory for quotient/transfer
authorhuffman
Sun, 22 Apr 2012 11:05:04 +0200
changeset 47660 7a5c681c0265
parent 47659 e3c4d1b0b351
child 47661 012a887997f3
child 47667 b4f71d8aecd6
new example theory for quotient/transfer
src/HOL/IsaMakefile
src/HOL/Library/Quotient_List.thy
src/HOL/Library/Quotient_Set.thy
src/HOL/Quotient_Examples/Lift_FSet.thy
src/HOL/Quotient_Examples/ROOT.ML
src/HOL/Transfer.thy
--- a/src/HOL/IsaMakefile	Sat Apr 21 21:38:08 2012 +0200
+++ b/src/HOL/IsaMakefile	Sun Apr 22 11:05:04 2012 +0200
@@ -1509,6 +1509,7 @@
   Quotient_Examples/DList.thy \
   Quotient_Examples/FSet.thy \
   Quotient_Examples/Quotient_Int.thy Quotient_Examples/Quotient_Message.thy \
+  Quotient_Examples/Lift_FSet.thy \
   Quotient_Examples/Lift_Set.thy Quotient_Examples/Lift_RBT.thy \
   Quotient_Examples/Lift_Fun.thy Quotient_Examples/Lift_DList.thy
 	@$(ISABELLE_TOOL) usedir $(OUT)/HOL Quotient_Examples
--- a/src/HOL/Library/Quotient_List.thy	Sat Apr 21 21:38:08 2012 +0200
+++ b/src/HOL/Library/Quotient_List.thy	Sun Apr 22 11:05:04 2012 +0200
@@ -22,6 +22,21 @@
     by (induct xs ys rule: list_induct2') simp_all
 qed
 
+lemma list_all2_OO: "list_all2 (A OO B) = list_all2 A OO list_all2 B"
+proof (intro ext iffI)
+  fix xs ys
+  assume "list_all2 (A OO B) xs ys"
+  thus "(list_all2 A OO list_all2 B) xs ys"
+    unfolding OO_def
+    by (induct, simp, simp add: list_all2_Cons1 list_all2_Cons2, fast)
+next
+  fix xs ys
+  assume "(list_all2 A OO list_all2 B) xs ys"
+  then obtain zs where "list_all2 A xs zs" and "list_all2 B zs ys" ..
+  thus "list_all2 (A OO B) xs ys"
+    by (induct arbitrary: ys, simp, clarsimp simp add: list_all2_Cons1, fast)
+qed
+
 lemma list_reflp:
   assumes "reflp R"
   shows "reflp (list_all2 R)"
--- a/src/HOL/Library/Quotient_Set.thy	Sat Apr 21 21:38:08 2012 +0200
+++ b/src/HOL/Library/Quotient_Set.thy	Sun Apr 22 11:05:04 2012 +0200
@@ -91,6 +91,10 @@
   "((A ===> B) ===> set_rel A ===> set_rel B) image image"
   unfolding fun_rel_def set_rel_def by simp fast
 
+lemma UNION_transfer [transfer_rule]:
+  "(set_rel A ===> (A ===> set_rel B) ===> set_rel B) UNION UNION"
+  unfolding SUP_def [abs_def] by transfer_prover
+
 lemma Ball_transfer [transfer_rule]:
   "(set_rel A ===> (A ===> op =) ===> op =) Ball Ball"
   unfolding set_rel_def fun_rel_def by fast
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/Quotient_Examples/Lift_FSet.thy	Sun Apr 22 11:05:04 2012 +0200
@@ -0,0 +1,285 @@
+(*  Title:      HOL/Quotient_Examples/Lift_FSet.thy
+    Author:     Brian Huffman, TU Munich
+*)
+
+header {* Lifting and transfer with a finite set type *}
+
+theory Lift_FSet
+imports "~~/src/HOL/Library/Quotient_List"
+begin
+
+subsection {* Equivalence relation and quotient type definition *}
+
+definition list_eq :: "'a list \<Rightarrow> 'a list \<Rightarrow> bool"
+  where [simp]: "list_eq xs ys \<longleftrightarrow> set xs = set ys"
+
+lemma reflp_list_eq: "reflp list_eq"
+  unfolding reflp_def by simp
+
+lemma symp_list_eq: "symp list_eq"
+  unfolding symp_def by simp
+
+lemma transp_list_eq: "transp list_eq"
+  unfolding transp_def by simp
+
+lemma equivp_list_eq: "equivp list_eq"
+  by (intro equivpI reflp_list_eq symp_list_eq transp_list_eq)
+
+quotient_type 'a fset = "'a list" / "list_eq"
+  by (rule equivp_list_eq)
+
+subsection {* Lifted constant definitions *}
+
+lift_definition fnil :: "'a fset" is "[]"
+  by simp
+
+lift_definition fcons :: "'a \<Rightarrow> 'a fset \<Rightarrow> 'a fset" is Cons
+  by simp
+
+lift_definition fappend :: "'a fset \<Rightarrow> 'a fset \<Rightarrow> 'a fset" is append
+  by simp
+
+lift_definition fmap :: "('a \<Rightarrow> 'b) \<Rightarrow> 'a fset \<Rightarrow> 'b fset" is map
+  by simp
+
+lift_definition ffilter :: "('a \<Rightarrow> bool) \<Rightarrow> 'a fset \<Rightarrow> 'a fset" is filter
+  by simp
+
+lift_definition fset :: "'a fset \<Rightarrow> 'a set" is set
+  by simp
+
+text {* Constants with nested types (like concat) yield a more
+  complicated proof obligation. *}
+
+lemma list_all2_cr_fset:
+  "list_all2 cr_fset xs ys \<longleftrightarrow> map abs_fset xs = ys"
+  unfolding cr_fset_def
+  apply safe
+  apply (erule list_all2_induct, simp, simp)
+  apply (simp add: list_all2_map2 List.list_all2_refl)
+  done
+
+lemma abs_fset_eq_iff: "abs_fset xs = abs_fset ys \<longleftrightarrow> list_eq xs ys"
+  using Quotient_rel [OF Quotient_fset] by simp
+
+lift_definition fconcat :: "'a fset fset \<Rightarrow> 'a fset" is concat
+proof -
+  fix xss yss :: "'a list list"
+  assume "(list_all2 cr_fset OO list_eq OO (list_all2 cr_fset)\<inverse>\<inverse>) xss yss"
+  then obtain uss vss where
+    "list_all2 cr_fset xss uss" and "list_eq uss vss" and
+    "list_all2 cr_fset yss vss" by clarsimp
+  hence "list_eq (map abs_fset xss) (map abs_fset yss)"
+    unfolding list_all2_cr_fset by simp
+  thus "list_eq (concat xss) (concat yss)"
+    apply (simp add: set_eq_iff image_def)
+    apply safe
+    apply (rename_tac xs, drule_tac x="abs_fset xs" in spec)
+    apply (drule iffD1, fast, clarsimp simp add: abs_fset_eq_iff, fast)
+    apply (rename_tac xs, drule_tac x="abs_fset xs" in spec)
+    apply (drule iffD2, fast, clarsimp simp add: abs_fset_eq_iff, fast)
+    done
+qed
+
+text {* Note that the generated transfer rule contains a composition
+  of relations. The transfer rule is not yet very useful in this form. *}
+
+lemma "(list_all2 cr_fset OO cr_fset ===> cr_fset) concat fconcat"
+  by (fact fconcat.transfer)
+
+
+subsection {* Using transfer with type @{text "fset"} *}
+
+text {* The correspondence relation @{text "cr_fset"} can only relate
+  @{text "list"} and @{text "fset"} types with the same element type.
+  To relate nested types like @{text "'a list list"} and
+  @{text "'a fset fset"}, we define a parameterized version of the
+  correspondence relation, @{text "cr_fset'"}. *}
+
+definition cr_fset' :: "('a \<Rightarrow> 'b \<Rightarrow> bool) \<Rightarrow> 'a list \<Rightarrow> 'b fset \<Rightarrow> bool"
+  where "cr_fset' R = list_all2 R OO cr_fset"
+
+lemma right_unique_cr_fset' [transfer_rule]:
+  "right_unique A \<Longrightarrow> right_unique (cr_fset' A)"
+  unfolding cr_fset'_def
+  by (intro right_unique_OO right_unique_list_all2 fset.right_unique)
+
+lemma right_total_cr_fset' [transfer_rule]:
+  "right_total A \<Longrightarrow> right_total (cr_fset' A)"
+  unfolding cr_fset'_def
+  by (intro right_total_OO right_total_list_all2 fset.right_total)
+
+lemma bi_total_cr_fset' [transfer_rule]:
+  "bi_total A \<Longrightarrow> bi_total (cr_fset' A)"
+  unfolding cr_fset'_def
+  by (intro bi_total_OO bi_total_list_all2 fset.bi_total)
+
+text {* Transfer rules for @{text "cr_fset'"} can be derived from the
+  existing transfer rules for @{text "cr_fset"} together with the
+  transfer rules for the polymorphic raw constants. *}
+
+text {* Note that the proofs below all have a similar structure and
+  could potentially be automated. *}
+
+lemma fnil_transfer [transfer_rule]:
+  "(cr_fset' A) [] fnil"
+  unfolding cr_fset'_def
+  apply (rule relcomppI)
+  apply (rule Nil_transfer)
+  apply (rule fnil.transfer)
+  done
+
+lemma fcons_transfer [transfer_rule]:
+  "(A ===> cr_fset' A ===> cr_fset' A) Cons fcons"
+  unfolding cr_fset'_def
+  apply (intro fun_relI)
+  apply (elim relcomppE)
+  apply (rule relcomppI)
+  apply (erule (1) Cons_transfer [THEN fun_relD, THEN fun_relD])
+  apply (erule fcons.transfer [THEN fun_relD, THEN fun_relD, OF refl])
+  done
+
+lemma fappend_transfer [transfer_rule]:
+  "(cr_fset' A ===> cr_fset' A ===> cr_fset' A) append fappend"
+  unfolding cr_fset'_def
+  apply (intro fun_relI)
+  apply (elim relcomppE)
+  apply (rule relcomppI)
+  apply (erule (1) append_transfer [THEN fun_relD, THEN fun_relD])
+  apply (erule (1) fappend.transfer [THEN fun_relD, THEN fun_relD])
+  done
+
+lemma fmap_transfer [transfer_rule]:
+  "((A ===> B) ===> cr_fset' A ===> cr_fset' B) map fmap"
+  unfolding cr_fset'_def
+  apply (intro fun_relI)
+  apply (elim relcomppE)
+  apply (rule relcomppI)
+  apply (erule (1) map_transfer [THEN fun_relD, THEN fun_relD])
+  apply (erule fmap.transfer [THEN fun_relD, THEN fun_relD, OF refl])
+  done
+
+lemma ffilter_transfer [transfer_rule]:
+  "((A ===> op =) ===> cr_fset' A ===> cr_fset' A) filter ffilter"
+  unfolding cr_fset'_def
+  apply (intro fun_relI)
+  apply (elim relcomppE)
+  apply (rule relcomppI)
+  apply (erule (1) filter_transfer [THEN fun_relD, THEN fun_relD])
+  apply (erule ffilter.transfer [THEN fun_relD, THEN fun_relD, OF refl])
+  done
+
+lemma fset_transfer [transfer_rule]:
+  "(cr_fset' A ===> set_rel A) set fset"
+  unfolding cr_fset'_def
+  apply (intro fun_relI)
+  apply (elim relcomppE)
+  apply (drule fset.transfer [THEN fun_relD])
+  apply (erule subst)
+  apply (erule set_transfer [THEN fun_relD])
+  done
+
+lemma fconcat_transfer [transfer_rule]:
+  "(cr_fset' (cr_fset' A) ===> cr_fset' A) concat fconcat"
+  unfolding cr_fset'_def
+  unfolding list_all2_OO
+  apply (intro fun_relI)
+  apply (elim relcomppE)
+  apply (rule relcomppI)
+  apply (erule concat_transfer [THEN fun_relD])
+  apply (rule fconcat.transfer [THEN fun_relD])
+  apply (erule (1) relcomppI)
+  done
+
+lemma list_eq_transfer [transfer_rule]:
+  assumes [transfer_rule]: "bi_unique A"
+  shows "(list_all2 A ===> list_all2 A ===> op =) list_eq list_eq"
+  unfolding list_eq_def [abs_def] by transfer_prover
+
+lemma fset_eq_transfer [transfer_rule]:
+  assumes "bi_unique A"
+  shows "(cr_fset' A ===> cr_fset' A ===> op =) list_eq (op =)"
+  unfolding cr_fset'_def
+  apply (intro fun_relI)
+  apply (elim relcomppE)
+  apply (rule trans)
+  apply (erule (1) list_eq_transfer [THEN fun_relD, THEN fun_relD, OF assms])
+  apply (erule (1) fset.rel_eq_transfer [THEN fun_relD, THEN fun_relD])
+  done
+
+text {* We don't need the original transfer rules any more: *}
+
+lemmas [transfer_rule del] =
+  fset.bi_total fset.right_total fset.right_unique
+  fnil.transfer fcons.transfer fappend.transfer fmap.transfer
+  ffilter.transfer fset.transfer fconcat.transfer fset.rel_eq_transfer
+
+subsection {* Transfer examples *}
+
+text {* The @{text "transfer"} method replaces equality on @{text
+  "fset"} with the @{text "list_eq"} relation on lists, which is
+  logically equivalent. *}
+
+lemma "fmap f (fmap g xs) = fmap (f \<circ> g) xs"
+  apply transfer
+  apply simp
+  done
+
+text {* The @{text "transfer'"} variant can replace equality on @{text
+  "fset"} with equality on @{text "list"}, which is logically stronger
+  but sometimes more convenient. *}
+
+lemma "fmap f (fmap g xs) = fmap (f \<circ> g) xs"
+  apply transfer'
+  apply (rule map_map)
+  done
+
+lemma "ffilter p (fmap f xs) = fmap f (ffilter (p \<circ> f) xs)"
+  apply transfer'
+  apply (rule filter_map)
+  done
+
+lemma "ffilter p (ffilter q xs) = ffilter (\<lambda>x. q x \<and> p x) xs"
+  apply transfer'
+  apply (rule filter_filter)
+  done
+
+lemma "fset (fcons x xs) = insert x (fset xs)"
+  apply transfer
+  apply (rule set.simps)
+  done
+
+lemma "fset (fappend xs ys) = fset xs \<union> fset ys"
+  apply transfer
+  apply (rule set_append)
+  done
+
+lemma "fset (fconcat xss) = (\<Union>xs\<in>fset xss. fset xs)"
+  apply transfer
+  apply (rule set_concat)
+  done
+
+lemma "\<forall>x\<in>fset xs. f x = g x \<Longrightarrow> fmap f xs = fmap g xs"
+  apply transfer
+  apply (simp cong: map_cong del: set_map)
+  done
+
+lemma "fnil = fconcat xss \<longleftrightarrow> (\<forall>xs\<in>fset xss. xs = fnil)"
+  apply transfer
+  apply simp
+  done
+
+lemma "fconcat (fmap (\<lambda>x. fcons x fnil) xs) = xs"
+  apply transfer'
+  apply simp
+  done
+
+lemma concat_map_concat: "concat (map concat xsss) = concat (concat xsss)"
+  by (induct xsss, simp_all)
+
+lemma "fconcat (fmap fconcat xss) = fconcat (fconcat xss)"
+  apply transfer'
+  apply (rule concat_map_concat)
+  done
+
+end
--- a/src/HOL/Quotient_Examples/ROOT.ML	Sat Apr 21 21:38:08 2012 +0200
+++ b/src/HOL/Quotient_Examples/ROOT.ML	Sun Apr 22 11:05:04 2012 +0200
@@ -4,6 +4,6 @@
 Testing the quotient package.
 *)
 
-use_thys ["DList", "FSet", "Quotient_Int", "Quotient_Message",
+use_thys ["DList", "FSet", "Quotient_Int", "Quotient_Message", "Lift_FSet",
   "Lift_Set", "Lift_RBT", "Lift_Fun", "Quotient_Rat", "Lift_DList"];
 
--- a/src/HOL/Transfer.thy	Sat Apr 21 21:38:08 2012 +0200
+++ b/src/HOL/Transfer.thy	Sun Apr 22 11:05:04 2012 +0200
@@ -153,6 +153,25 @@
   "bi_unique R \<longleftrightarrow> (R ===> R ===> op =) (op =) (op =)"
   unfolding bi_unique_def fun_rel_def by auto
 
+text {* Properties are preserved by relation composition. *}
+
+lemma OO_def: "R OO S = (\<lambda>x z. \<exists>y. R x y \<and> S y z)"
+  by auto
+
+lemma bi_total_OO: "\<lbrakk>bi_total A; bi_total B\<rbrakk> \<Longrightarrow> bi_total (A OO B)"
+  unfolding bi_total_def OO_def by metis
+
+lemma bi_unique_OO: "\<lbrakk>bi_unique A; bi_unique B\<rbrakk> \<Longrightarrow> bi_unique (A OO B)"
+  unfolding bi_unique_def OO_def by metis
+
+lemma right_total_OO:
+  "\<lbrakk>right_total A; right_total B\<rbrakk> \<Longrightarrow> right_total (A OO B)"
+  unfolding right_total_def OO_def by metis
+
+lemma right_unique_OO:
+  "\<lbrakk>right_unique A; right_unique B\<rbrakk> \<Longrightarrow> right_unique (A OO B)"
+  unfolding right_unique_def OO_def by metis
+
 
 subsection {* Properties of relators *}