# HG changeset patch
# User paulson
# Date 1088092493 -7200
# Node ID 546c8e7e28d40c35101f44388e4d849c173f2574
# Parent  44ac09ba7213a9c3c8577b87115401e0a92ed587
Norbert Voelker

diff -r 44ac09ba7213 -r 546c8e7e28d4 src/HOL/Library/Permutation.thy
--- a/src/HOL/Library/Permutation.thy	Thu Jun 24 17:52:55 2004 +0200
+++ b/src/HOL/Library/Permutation.thy	Thu Jun 24 17:54:53 2004 +0200
@@ -1,15 +1,10 @@
 (*  Title:      HOL/Library/Permutation.thy
-    ID:         $Id$
-    Author:     Lawrence C Paulson and Thomas M Rasmussen
-    Copyright   1995  University of Cambridge
-
-TODO: it would be nice to prove (for "multiset", defined on
-HOL/ex/Sorting.thy) xs <~~> ys = (\<forall>x. multiset xs x = multiset ys x)
+    Author:     Lawrence C Paulson and Thomas M Rasmussen and Norbert Voelker
 *)
 
 header {* Permutations *}
 
-theory Permutation = Main:
+theory Permutation = Multiset:
 
 consts
   perm :: "('a list * 'a list) set"
@@ -27,9 +22,7 @@
     trans [intro]: "xs <~~> ys ==> ys <~~> zs ==> xs <~~> zs"
 
 lemma perm_refl [iff]: "l <~~> l"
-  apply (induct l)
-   apply auto
-  done
+by (induct l, auto)
 
 
 subsection {* Some examples of rule induction on permutations *}
@@ -41,9 +34,7 @@
   done
 
 lemma xperm_empty_imp: "[] <~~> ys ==> ys = []"
-  apply (insert xperm_empty_imp_aux)
-  apply blast
-  done
+by (insert xperm_empty_imp_aux, blast)
 
 
 text {*
@@ -51,24 +42,16 @@
   *}
 
 lemma perm_length: "xs <~~> ys ==> length xs = length ys"
-  apply (erule perm.induct)
-     apply simp_all
-  done
+by (erule perm.induct, simp_all)
 
 lemma perm_empty_imp: "[] <~~> xs ==> xs = []"
-  apply (drule perm_length)
-  apply auto
-  done
+by (drule perm_length, auto)
 
 lemma perm_sym: "xs <~~> ys ==> ys <~~> xs"
-  apply (erule perm.induct)
-     apply auto
-  done
+by (erule perm.induct, auto)
 
 lemma perm_mem [rule_format]: "xs <~~> ys ==> x mem xs --> x mem ys"
-  apply (erule perm.induct)
-     apply auto
-  done
+by (erule perm.induct, auto)
 
 
 subsection {* Ways of making new permutations *}
@@ -78,44 +61,35 @@
 *}
 
 lemma perm_append_Cons: "a # xs @ ys <~~> xs @ a # ys"
-  apply (induct xs)
-   apply auto
-  done
+by (induct xs, auto)
 
 lemma perm_append_swap: "xs @ ys <~~> ys @ xs"
-  apply (induct xs)
-    apply simp_all
+  apply (induct xs, simp_all)
   apply (blast intro: perm_append_Cons)
   done
 
 lemma perm_append_single: "a # xs <~~> xs @ [a]"
   apply (rule perm.trans)
    prefer 2
-   apply (rule perm_append_swap)
-  apply simp
+   apply (rule perm_append_swap, simp)
   done
 
 lemma perm_rev: "rev xs <~~> xs"
-  apply (induct xs)
-   apply simp_all
+  apply (induct xs, simp_all)
   apply (blast intro!: perm_append_single intro: perm_sym)
   done
 
 lemma perm_append1: "xs <~~> ys ==> l @ xs <~~> l @ ys"
-  apply (induct l)
-   apply auto
-  done
+by (induct l, auto)
 
 lemma perm_append2: "xs <~~> ys ==> xs @ l <~~> ys @ l"
-  apply (blast intro!: perm_append_swap perm_append1)
-  done
+by (blast intro!: perm_append_swap perm_append1)
 
 
 subsection {* Further results *}
 
 lemma perm_empty [iff]: "([] <~~> xs) = (xs = [])"
-  apply (blast intro: perm_empty_imp)
-  done
+by (blast intro: perm_empty_imp)
 
 lemma perm_empty2 [iff]: "(xs <~~> []) = (xs = [])"
   apply auto
@@ -123,17 +97,13 @@
   done
 
 lemma perm_sing_imp [rule_format]: "ys <~~> xs ==> xs = [y] --> ys = [y]"
-  apply (erule perm.induct)
-     apply auto
-  done
+by (erule perm.induct, auto)
 
 lemma perm_sing_eq [iff]: "(ys <~~> [y]) = (ys = [y])"
-  apply (blast intro: perm_sing_imp)
-  done
+by (blast intro: perm_sing_imp)
 
 lemma perm_sing_eq2 [iff]: "([y] <~~> ys) = (ys = [y])"
-  apply (blast dest: perm_sym)
-  done
+by (blast dest: perm_sym)
 
 
 subsection {* Removing elements *}
@@ -145,35 +115,26 @@
   "remove x (y # ys) = (if x = y then ys else y # remove x ys)"
 
 lemma perm_remove: "x \<in> set ys ==> ys <~~> x # remove x ys"
-  apply (induct ys)
-   apply auto
-  done
+by (induct ys, auto)
 
 lemma remove_commute: "remove x (remove y l) = remove y (remove x l)"
-  apply (induct l)
-   apply auto
-  done
+by (induct l, auto)
 
 
 text {* \medskip Congruence rule *}
 
 lemma perm_remove_perm: "xs <~~> ys ==> remove z xs <~~> remove z ys"
-  apply (erule perm.induct)
-     apply auto
-  done
+by (erule perm.induct, auto)
 
 lemma remove_hd [simp]: "remove z (z # xs) = xs"
   apply auto
   done
 
 lemma cons_perm_imp_perm: "z # xs <~~> z # ys ==> xs <~~> ys"
-  apply (drule_tac z = z in perm_remove_perm)
-  apply auto
-  done
+by (drule_tac z = z in perm_remove_perm, auto)
 
 lemma cons_perm_eq [iff]: "(z#xs <~~> z#ys) = (xs <~~> ys)"
-  apply (blast intro: cons_perm_imp_perm)
-  done
+by (blast intro: cons_perm_imp_perm)
 
 lemma append_perm_imp_perm: "!!xs ys. zs @ xs <~~> zs @ ys ==> xs <~~> ys"
   apply (induct zs rule: rev_induct)
@@ -182,8 +143,7 @@
   done
 
 lemma perm_append1_eq [iff]: "(zs @ xs <~~> zs @ ys) = (xs <~~> ys)"
-  apply (blast intro: append_perm_imp_perm perm_append1)
-  done
+by (blast intro: append_perm_imp_perm perm_append1)
 
 lemma perm_append2_eq [iff]: "(xs @ zs <~~> ys @ zs) = (xs <~~> ys)"
   apply (safe intro!: perm_append2)
@@ -193,4 +153,47 @@
   apply (blast intro: perm_append_swap)
   done
 
+(****************** Norbert Voelker 17 June 2004 **************) 
+
+consts 
+  multiset_of :: "'a list \<Rightarrow> 'a multiset"
+primrec
+  "multiset_of [] = {#}"
+  "multiset_of (a # x) = multiset_of x + {# a #}"
+
+lemma multiset_of_zero_iff[simp]: "(multiset_of x = {#}) = (x = [])"
+  by (induct_tac x, auto) 
+
+lemma multiset_of_zero_iff_right[simp]: "({#} = multiset_of x) = (x = [])"
+  by (induct_tac x, auto)
+
+lemma set_of_multiset_of[simp]: "set_of(multiset_of x) = set x"
+ by (induct_tac x, auto) 
+
+lemma multiset_of_remove[simp]: 
+  "multiset_of (remove a x) = multiset_of x - {#a#}"
+  by (induct_tac x, auto simp: multiset_eq_conv_count_eq) 
+
+lemma multiset_of_eq_perm:  "(multiset_of xs = multiset_of ys) = (xs <~~> ys) "
+  apply (rule iffI) 
+  apply (erule_tac [2] perm.induct, simp_all add: union_ac) 
+  apply (erule rev_mp, rule_tac x=ys in spec, induct_tac xs, auto) 
+  apply (erule_tac x = "remove a x" in allE, drule sym, simp) 
+  apply (subgoal_tac "a \<in> set x") 
+  apply (drule_tac z=a in perm.Cons) 
+  apply (erule perm.trans, rule perm_sym, erule perm_remove) 
+  apply (drule_tac f=set_of in arg_cong, simp)
+  done
+
+lemma set_count_multiset_of: "set x = {a. 0 < count (multiset_of x) a}"
+  by (induct_tac x, auto)  
+
+lemma distinct_count_multiset_of: 
+   "distinct x \<Longrightarrow> count (multiset_of x) a = (if a \<in> set x then 1 else 0)"
+  by (erule rev_mp, induct_tac x, auto) 
+
+lemma distinct_set_eq_iff_multiset_of_eq: 
+  "\<lbrakk>distinct x; distinct y\<rbrakk> \<Longrightarrow> (set x = set y) = (multiset_of x = multiset_of y)"
+  by (auto simp: multiset_eq_conv_count_eq distinct_count_multiset_of) 
+
 end