src/HOL/Library/Multiset.thy
author wenzelm
Wed Oct 18 23:28:33 2000 +0200 (2000-10-18)
changeset 10249 e4d13d8a9011
child 10277 081c8641aa11
permissions -rw-r--r--
Multisets (from HOL/Induct/Multiset and friends);
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(*  Title:      HOL/Library/Multiset.thy
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    ID:         $Id$
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    Author:     Tobias Nipkow, TU Muenchen
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    Author:     Markus Wenzel, TU Muenchen
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    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
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*)
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header {*
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 \title{Multisets}
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 \author{Tobias Nipkow, Markus Wenzel, and Lawrence C Paulson}
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*}
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theory Multiset = Accessible_Part:
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subsection {* The type of multisets *}
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typedef 'a multiset = "{f::'a => nat. finite {x . 0 < f x}}"
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proof
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  show "(\<lambda>x. 0::nat) \<in> {f. finite {x. 0 < f x}}"
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    by simp
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qed
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lemmas multiset_typedef [simp] =
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  Abs_multiset_inverse Rep_multiset_inverse Rep_multiset
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constdefs
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  Mempty :: "'a multiset"    ("{#}")
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  "{#} == Abs_multiset (\<lambda>a. 0)"
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  single :: "'a => 'a multiset"    ("{#_#}")
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  "{#a#} == Abs_multiset (\<lambda>b. if b = a then 1 else 0)"
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  count :: "'a multiset => 'a => nat"
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  "count == Rep_multiset"
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  MCollect :: "'a multiset => ('a => bool) => 'a multiset"
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  "MCollect M P == Abs_multiset (\<lambda>x. if P x then Rep_multiset M x else 0)"
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syntax
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  "_Melem" :: "'a => 'a multiset => bool"    ("(_/ :# _)" [50, 51] 50)
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  "_MCollect" :: "pttrn => 'a multiset => bool => 'a multiset"    ("(1{# _ : _./ _#})")
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translations
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  "a :# M" == "0 < count M a"
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  "{#x:M. P#}" == "MCollect M (\<lambda>x. P)"
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constdefs
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  set_of :: "'a multiset => 'a set"
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  "set_of M == {x. x :# M}"
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instance multiset :: ("term") plus by intro_classes
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instance multiset :: ("term") minus by intro_classes
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instance multiset :: ("term") zero by intro_classes
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defs (overloaded)
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  union_def: "M + N == Abs_multiset (\<lambda>a. Rep_multiset M a + Rep_multiset N a)"
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  diff_def: "M - N == Abs_multiset (\<lambda>a. Rep_multiset M a - Rep_multiset N a)"
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  Zero_def [simp]: "0 == {#}"
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  size_def: "size M == setsum (count M) (set_of M)"
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text {*
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 \medskip Preservation of the representing set @{term multiset}.
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*}
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lemma const0_in_multiset [simp]: "(\<lambda>a. 0) \<in> multiset"
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  apply (simp add: multiset_def)
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  done
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lemma only1_in_multiset [simp]: "(\<lambda>b. if b = a then 1 else 0) \<in> multiset"
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  apply (simp add: multiset_def)
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  done
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lemma union_preserves_multiset [simp]:
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    "M \<in> multiset ==> N \<in> multiset ==> (\<lambda>a. M a + N a) \<in> multiset"
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  apply (unfold multiset_def)
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  apply simp
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  apply (drule finite_UnI)
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   apply assumption
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  apply (simp del: finite_Un add: Un_def)
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  done
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lemma diff_preserves_multiset [simp]:
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    "M \<in> multiset ==> (\<lambda>a. M a - N a) \<in> multiset"
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  apply (unfold multiset_def)
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  apply simp
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  apply (rule finite_subset)
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   prefer 2
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   apply assumption
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  apply auto
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  done
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text {*
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 \medskip Injectivity of @{term Rep_multiset}.
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*}  (* FIXME typedef package (!?) *)
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lemma multiset_eq_conv_Rep_eq [simp]:
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    "(M = N) = (Rep_multiset M = Rep_multiset N)"
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  apply (rule iffI)
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   apply simp
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  apply (drule_tac f = Abs_multiset in arg_cong)
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  apply simp
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  done
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(* FIXME
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Goal
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 "[| f : multiset; g : multiset |] ==> \
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\ (Abs_multiset f = Abs_multiset g) = (!x. f x = g x)";
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by (rtac iffI 1);
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 by (dres_inst_tac [("f","Rep_multiset")] arg_cong 1);
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 by (Asm_full_simp_tac 1);
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by (subgoal_tac "f = g" 1);
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 by (Asm_simp_tac 1);
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by (rtac ext 1);
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by (Blast_tac 1);
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qed "Abs_multiset_eq";
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Addsimps [Abs_multiset_eq];
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*)
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subsection {* Algebraic properties of multisets *}
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subsubsection {* Union *}
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theorem union_empty [simp]: "M + {#} = M \<and> {#} + M = M"
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  apply (simp add: union_def Mempty_def)
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  done
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theorem union_commute: "M + N = N + (M::'a multiset)"
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  apply (simp add: union_def add_ac)
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  done
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theorem union_assoc: "(M + N) + K = M + (N + (K::'a multiset))"
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  apply (simp add: union_def add_ac)
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  done
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theorem union_lcomm: "M + (N + K) = N + (M + (K::'a multiset))"
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  apply (rule union_commute [THEN trans])
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  apply (rule union_assoc [THEN trans])
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  apply (rule union_commute [THEN arg_cong])
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  done
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theorems union_ac = union_assoc union_commute union_lcomm
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subsubsection {* Difference *}
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theorem diff_empty [simp]: "M - {#} = M \<and> {#} - M = {#}"
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  apply (simp add: Mempty_def diff_def)
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  done
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theorem diff_union_inverse2 [simp]: "M + {#a#} - {#a#} = M"
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  apply (simp add: union_def diff_def)
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  done
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subsubsection {* Count of elements *}
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theorem count_empty [simp]: "count {#} a = 0"
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  apply (simp add: count_def Mempty_def)
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  done
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theorem count_single [simp]: "count {#b#} a = (if b = a then 1 else 0)"
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  apply (simp add: count_def single_def)
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  done
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theorem count_union [simp]: "count (M + N) a = count M a + count N a"
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  apply (simp add: count_def union_def)
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  done
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theorem count_diff [simp]: "count (M - N) a = count M a - count N a"
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  apply (simp add: count_def diff_def)
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  done
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subsubsection {* Set of elements *}
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theorem set_of_empty [simp]: "set_of {#} = {}"
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  apply (simp add: set_of_def)
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  done
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theorem set_of_single [simp]: "set_of {#b#} = {b}"
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  apply (simp add: set_of_def)
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  done
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theorem set_of_union [simp]: "set_of (M + N) = set_of M \<union> set_of N"
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  apply (auto simp add: set_of_def)
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  done
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theorem set_of_eq_empty_iff [simp]: "(set_of M = {}) = (M = {#})"
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  apply (auto simp add: set_of_def Mempty_def count_def expand_fun_eq)
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  done
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theorem mem_set_of_iff [simp]: "(x \<in> set_of M) = (x :# M)"
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  apply (auto simp add: set_of_def)
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  done
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subsubsection {* Size *}
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theorem size_empty [simp]: "size {#} = 0"
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  apply (simp add: size_def)
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  done
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theorem size_single [simp]: "size {#b#} = 1"
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  apply (simp add: size_def)
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  done
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theorem finite_set_of [iff]: "finite (set_of M)"
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  apply (cut_tac x = M in Rep_multiset)
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  apply (simp add: multiset_def set_of_def count_def)
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  done
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theorem setsum_count_Int:
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    "finite A ==> setsum (count N) (A \<inter> set_of N) = setsum (count N) A"
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  apply (erule finite_induct)
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   apply simp
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  apply (simp add: Int_insert_left set_of_def)
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  done
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theorem size_union [simp]: "size (M + N::'a multiset) = size M + size N"
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  apply (unfold size_def)
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  apply (subgoal_tac "count (M + N) = (\<lambda>a. count M a + count N a)")
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   prefer 2
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   apply (rule ext)
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   apply simp
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  apply (simp (no_asm_simp) add: setsum_Un setsum_addf setsum_count_Int)
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  apply (subst Int_commute)
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  apply (simp (no_asm_simp) add: setsum_count_Int)
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  done
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theorem size_eq_0_iff_empty [iff]: "(size M = 0) = (M = {#})"
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  apply (unfold size_def Mempty_def count_def)
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  apply auto
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  apply (simp add: set_of_def count_def expand_fun_eq)
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  done
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theorem size_eq_Suc_imp_elem: "size M = Suc n ==> \<exists>a. a :# M"
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  apply (unfold size_def)
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  apply (drule setsum_SucD)
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  apply auto
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  done
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subsubsection {* Equality of multisets *}
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theorem multiset_eq_conv_count_eq: "(M = N) = (\<forall>a. count M a = count N a)"
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  apply (simp add: count_def expand_fun_eq)
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  done
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theorem single_not_empty [simp]: "{#a#} \<noteq> {#} \<and> {#} \<noteq> {#a#}"
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  apply (simp add: single_def Mempty_def expand_fun_eq)
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  done
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theorem single_eq_single [simp]: "({#a#} = {#b#}) = (a = b)"
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  apply (auto simp add: single_def expand_fun_eq)
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  done
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theorem union_eq_empty [iff]: "(M + N = {#}) = (M = {#} \<and> N = {#})"
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  apply (auto simp add: union_def Mempty_def expand_fun_eq)
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  done
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theorem empty_eq_union [iff]: "({#} = M + N) = (M = {#} \<and> N = {#})"
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  apply (auto simp add: union_def Mempty_def expand_fun_eq)
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  done
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theorem union_right_cancel [simp]: "(M + K = N + K) = (M = (N::'a multiset))"
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  apply (simp add: union_def expand_fun_eq)
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  done
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theorem union_left_cancel [simp]: "(K + M = K + N) = (M = (N::'a multiset))"
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  apply (simp add: union_def expand_fun_eq)
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  done
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theorem union_is_single:
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    "(M + N = {#a#}) = (M = {#a#} \<and> N={#} \<or> M = {#} \<and> N = {#a#})"
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  apply (unfold Mempty_def single_def union_def)
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  apply (simp add: add_is_1 expand_fun_eq)
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  apply blast
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  done
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theorem single_is_union:
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  "({#a#} = M + N) =
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    ({#a#} = M \<and> N = {#} \<or> M = {#} \<and> {#a#} = N)"
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  apply (unfold Mempty_def single_def union_def)
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  apply (simp add: one_is_add expand_fun_eq)
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  apply (blast dest: sym)
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  done
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theorem add_eq_conv_diff:
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  "(M + {#a#} = N + {#b#}) =
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    (M = N \<and> a = b \<or>
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      M = N - {#a#} + {#b#} \<and> N = M - {#b#} + {#a#})"
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  apply (unfold single_def union_def diff_def)
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  apply (simp (no_asm) add: expand_fun_eq)
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  apply (rule conjI)
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   apply force
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  apply clarify
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  apply (rule conjI)
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   apply blast
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  apply clarify
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  apply (rule iffI)
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   apply (rule conjI)
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    apply clarify
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    apply (rule conjI)
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     apply (simp add: eq_sym_conv)   (* FIXME blast fails !? *)
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    apply fast
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   apply simp
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  apply force
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  done
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(*
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val prems = Goal
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 "[| !!F. [| finite F; !G. G < F --> P G |] ==> P F |] ==> finite F --> P F";
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by (res_inst_tac [("a","F"),("f","\<lambda>A. if finite A then card A else 0")]
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     measure_induct 1);
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by (Clarify_tac 1);
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by (resolve_tac prems 1);
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 by (assume_tac 1);
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by (Clarify_tac 1);
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by (subgoal_tac "finite G" 1);
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 by (fast_tac (claset() addDs [finite_subset,order_less_le RS iffD1]) 2);
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by (etac allE 1);
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by (etac impE 1);
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 by (Blast_tac 2);
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by (asm_simp_tac (simpset() addsimps [psubset_card]) 1);
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no_qed();
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val lemma = result();
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val prems = Goal
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 "[| finite F; !!F. [| finite F; !G. G < F --> P G |] ==> P F |] ==> P F";
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by (rtac (lemma RS mp) 1);
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by (REPEAT(ares_tac prems 1));
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qed "finite_psubset_induct";
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Better: use wf_finite_psubset in WF_Rel
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*)
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subsection {* Induction over multisets *}
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lemma setsum_decr:
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  "finite F ==> 0 < f a ==>
wenzelm@10249
   343
    setsum (f (a := f a - 1)) F = (if a \<in> F then setsum f F - 1 else setsum f F)"
wenzelm@10249
   344
  apply (erule finite_induct)
wenzelm@10249
   345
   apply auto
wenzelm@10249
   346
  apply (drule_tac a = a in mk_disjoint_insert)
wenzelm@10249
   347
  apply auto
wenzelm@10249
   348
  done
wenzelm@10249
   349
wenzelm@10249
   350
lemma Rep_multiset_induct_aux:
wenzelm@10249
   351
  "P (\<lambda>a. 0) ==> (!!f b. f \<in> multiset ==> P f ==> P (f (b := f b + 1)))
wenzelm@10249
   352
    ==> \<forall>f. f \<in> multiset --> setsum f {x. 0 < f x} = n --> P f"
wenzelm@10249
   353
proof -
wenzelm@10249
   354
  case antecedent
wenzelm@10249
   355
  note prems = this [unfolded multiset_def]
wenzelm@10249
   356
  show ?thesis
wenzelm@10249
   357
    apply (unfold multiset_def)
wenzelm@10249
   358
    apply (induct_tac n)
wenzelm@10249
   359
     apply simp
wenzelm@10249
   360
     apply clarify
wenzelm@10249
   361
     apply (subgoal_tac "f = (\<lambda>a.0)")
wenzelm@10249
   362
      apply simp
wenzelm@10249
   363
      apply (rule prems)
wenzelm@10249
   364
     apply (rule ext)
wenzelm@10249
   365
     apply force
wenzelm@10249
   366
    apply clarify
wenzelm@10249
   367
    apply (frule setsum_SucD)
wenzelm@10249
   368
    apply clarify
wenzelm@10249
   369
    apply (rename_tac a)
wenzelm@10249
   370
    apply (subgoal_tac "finite {x. 0 < (f (a := f a - 1)) x}")
wenzelm@10249
   371
     prefer 2
wenzelm@10249
   372
     apply (rule finite_subset)
wenzelm@10249
   373
      prefer 2
wenzelm@10249
   374
      apply assumption
wenzelm@10249
   375
     apply simp
wenzelm@10249
   376
     apply blast
wenzelm@10249
   377
    apply (subgoal_tac "f = (f (a := f a - 1))(a := (f (a := f a - 1)) a + 1)")
wenzelm@10249
   378
     prefer 2
wenzelm@10249
   379
     apply (rule ext)
wenzelm@10249
   380
     apply (simp (no_asm_simp))
wenzelm@10249
   381
     apply (erule ssubst, rule prems)
wenzelm@10249
   382
     apply blast
wenzelm@10249
   383
    apply (erule allE, erule impE, erule_tac [2] mp)
wenzelm@10249
   384
     apply blast
wenzelm@10249
   385
    apply (simp (no_asm_simp) add: setsum_decr del: fun_upd_apply)
wenzelm@10249
   386
    apply (subgoal_tac "{x. x \<noteq> a --> 0 < f x} = {x. 0 < f x}")
wenzelm@10249
   387
     prefer 2
wenzelm@10249
   388
     apply blast
wenzelm@10249
   389
    apply (subgoal_tac "{x. x \<noteq> a \<and> 0 < f x} = {x. 0 < f x} - {a}")
wenzelm@10249
   390
     prefer 2
wenzelm@10249
   391
     apply blast
wenzelm@10249
   392
    apply (simp add: le_imp_diff_is_add setsum_diff1 cong: conj_cong)
wenzelm@10249
   393
    done
wenzelm@10249
   394
qed
wenzelm@10249
   395
wenzelm@10249
   396
theorem Rep_multiset_induct:
wenzelm@10249
   397
  "f \<in> multiset ==> P (\<lambda>a. 0) ==>
wenzelm@10249
   398
    (!!f b. f \<in> multiset ==> P f ==> P (f (b := f b + 1))) ==> P f"
wenzelm@10249
   399
  apply (insert Rep_multiset_induct_aux)
wenzelm@10249
   400
  apply blast
wenzelm@10249
   401
  done
wenzelm@10249
   402
wenzelm@10249
   403
theorem multiset_induct [induct type: multiset]:
wenzelm@10249
   404
  "P {#} ==> (!!M x. P M ==> P (M + {#x#})) ==> P M"
wenzelm@10249
   405
proof -
wenzelm@10249
   406
  note defns = union_def single_def Mempty_def
wenzelm@10249
   407
  assume prem1 [unfolded defns]: "P {#}"
wenzelm@10249
   408
  assume prem2 [unfolded defns]: "!!M x. P M ==> P (M + {#x#})"
wenzelm@10249
   409
  show ?thesis
wenzelm@10249
   410
    apply (rule Rep_multiset_inverse [THEN subst])
wenzelm@10249
   411
    apply (rule Rep_multiset [THEN Rep_multiset_induct])
wenzelm@10249
   412
     apply (rule prem1)
wenzelm@10249
   413
    apply (subgoal_tac "f (b := f b + 1) = (\<lambda>a. f a + (if a = b then 1 else 0))")
wenzelm@10249
   414
     prefer 2
wenzelm@10249
   415
     apply (simp add: expand_fun_eq)
wenzelm@10249
   416
    apply (erule ssubst)
wenzelm@10249
   417
    apply (erule Abs_multiset_inverse [THEN subst])
wenzelm@10249
   418
    apply (erule prem2 [simplified])
wenzelm@10249
   419
    done
wenzelm@10249
   420
qed
wenzelm@10249
   421
wenzelm@10249
   422
wenzelm@10249
   423
lemma MCollect_preserves_multiset:
wenzelm@10249
   424
    "M \<in> multiset ==> (\<lambda>x. if P x then M x else 0) \<in> multiset"
wenzelm@10249
   425
  apply (simp add: multiset_def)
wenzelm@10249
   426
  apply (rule finite_subset)
wenzelm@10249
   427
   apply auto
wenzelm@10249
   428
  done
wenzelm@10249
   429
wenzelm@10249
   430
theorem count_MCollect [simp]:
wenzelm@10249
   431
    "count {# x:M. P x #} a = (if P a then count M a else 0)"
wenzelm@10249
   432
  apply (unfold count_def MCollect_def)
wenzelm@10249
   433
  apply (simp add: MCollect_preserves_multiset)
wenzelm@10249
   434
  done
wenzelm@10249
   435
wenzelm@10249
   436
theorem set_of_MCollect [simp]: "set_of {# x:M. P x #} = set_of M \<inter> {x. P x}"
wenzelm@10249
   437
  apply (auto simp add: set_of_def)
wenzelm@10249
   438
  done
wenzelm@10249
   439
wenzelm@10249
   440
theorem multiset_partition: "M = {# x:M. P x #} + {# x:M. \<not> P x #}"
wenzelm@10249
   441
  apply (subst multiset_eq_conv_count_eq)
wenzelm@10249
   442
  apply auto
wenzelm@10249
   443
  done
wenzelm@10249
   444
wenzelm@10249
   445
declare multiset_eq_conv_Rep_eq [simp del]
wenzelm@10249
   446
declare multiset_typedef [simp del]
wenzelm@10249
   447
wenzelm@10249
   448
theorem add_eq_conv_ex:
wenzelm@10249
   449
  "(M + {#a#} = N + {#b#}) =
wenzelm@10249
   450
    (M = N \<and> a = b \<or> (\<exists>K. M = K + {#b#} \<and> N = K + {#a#}))"
wenzelm@10249
   451
  apply (auto simp add: add_eq_conv_diff)
wenzelm@10249
   452
  done
wenzelm@10249
   453
wenzelm@10249
   454
wenzelm@10249
   455
subsection {* Multiset orderings *}
wenzelm@10249
   456
wenzelm@10249
   457
subsubsection {* Well-foundedness *}
wenzelm@10249
   458
wenzelm@10249
   459
constdefs
wenzelm@10249
   460
  mult1 :: "('a \<times> 'a) set => ('a multiset \<times> 'a multiset) set"
wenzelm@10249
   461
  "mult1 r ==
wenzelm@10249
   462
    {(N, M). \<exists>a M0 K. M = M0 + {#a#} \<and> N = M0 + K \<and>
wenzelm@10249
   463
      (\<forall>b. b :# K --> (b, a) \<in> r)}"
wenzelm@10249
   464
wenzelm@10249
   465
  mult :: "('a \<times> 'a) set => ('a multiset \<times> 'a multiset) set"
wenzelm@10249
   466
  "mult r == (mult1 r)^+"
wenzelm@10249
   467
wenzelm@10249
   468
lemma not_less_empty [iff]: "(M, {#}) \<notin> mult1 r"
wenzelm@10249
   469
  apply (simp add: mult1_def)
wenzelm@10249
   470
  done
wenzelm@10249
   471
wenzelm@10249
   472
lemma less_add: "(N, M0 + {#a#}) \<in> mult1 r ==>
wenzelm@10249
   473
    (\<exists>M. (M, M0) \<in> mult1 r \<and> N = M + {#a#}) \<or>
wenzelm@10249
   474
    (\<exists>K. (\<forall>b. b :# K --> (b, a) \<in> r) \<and> N = M0 + K)"
wenzelm@10249
   475
  (concl is "?case1 (mult1 r) \<or> ?case2")
wenzelm@10249
   476
proof (unfold mult1_def)
wenzelm@10249
   477
  let ?r = "\<lambda>K a. \<forall>b. b :# K --> (b, a) \<in> r"
wenzelm@10249
   478
  let ?R = "\<lambda>N M. \<exists>a M0 K. M = M0 + {#a#} \<and> N = M0 + K \<and> ?r K a"
wenzelm@10249
   479
  let ?case1 = "?case1 {(N, M). ?R N M}"
wenzelm@10249
   480
wenzelm@10249
   481
  assume "(N, M0 + {#a#}) \<in> {(N, M). ?R N M}"
wenzelm@10249
   482
  hence "\<exists>a' M0' K.
wenzelm@10249
   483
      M0 + {#a#} = M0' + {#a'#} \<and> N = M0' + K \<and> ?r K a'" by simp
wenzelm@10249
   484
  thus "?case1 \<or> ?case2"
wenzelm@10249
   485
  proof (elim exE conjE)
wenzelm@10249
   486
    fix a' M0' K
wenzelm@10249
   487
    assume N: "N = M0' + K" and r: "?r K a'"
wenzelm@10249
   488
    assume "M0 + {#a#} = M0' + {#a'#}"
wenzelm@10249
   489
    hence "M0 = M0' \<and> a = a' \<or>
wenzelm@10249
   490
        (\<exists>K'. M0 = K' + {#a'#} \<and> M0' = K' + {#a#})"
wenzelm@10249
   491
      by (simp only: add_eq_conv_ex)
wenzelm@10249
   492
    thus ?thesis
wenzelm@10249
   493
    proof (elim disjE conjE exE)
wenzelm@10249
   494
      assume "M0 = M0'" "a = a'"
wenzelm@10249
   495
      with N r have "?r K a \<and> N = M0 + K" by simp
wenzelm@10249
   496
      hence ?case2 .. thus ?thesis ..
wenzelm@10249
   497
    next
wenzelm@10249
   498
      fix K'
wenzelm@10249
   499
      assume "M0' = K' + {#a#}"
wenzelm@10249
   500
      with N have n: "N = K' + K + {#a#}" by (simp add: union_ac)
wenzelm@10249
   501
wenzelm@10249
   502
      assume "M0 = K' + {#a'#}"
wenzelm@10249
   503
      with r have "?R (K' + K) M0" by blast
wenzelm@10249
   504
      with n have ?case1 by simp thus ?thesis ..
wenzelm@10249
   505
    qed
wenzelm@10249
   506
  qed
wenzelm@10249
   507
qed
wenzelm@10249
   508
wenzelm@10249
   509
lemma all_accessible: "wf r ==> \<forall>M. M \<in> acc (mult1 r)"
wenzelm@10249
   510
proof
wenzelm@10249
   511
  let ?R = "mult1 r"
wenzelm@10249
   512
  let ?W = "acc ?R"
wenzelm@10249
   513
  {
wenzelm@10249
   514
    fix M M0 a
wenzelm@10249
   515
    assume M0: "M0 \<in> ?W"
wenzelm@10249
   516
      and wf_hyp: "\<forall>b. (b, a) \<in> r --> (\<forall>M \<in> ?W. M + {#b#} \<in> ?W)"
wenzelm@10249
   517
      and acc_hyp: "\<forall>M. (M, M0) \<in> ?R --> M + {#a#} \<in> ?W"
wenzelm@10249
   518
    have "M0 + {#a#} \<in> ?W"
wenzelm@10249
   519
    proof (rule accI [of "M0 + {#a#}"])
wenzelm@10249
   520
      fix N
wenzelm@10249
   521
      assume "(N, M0 + {#a#}) \<in> ?R"
wenzelm@10249
   522
      hence "((\<exists>M. (M, M0) \<in> ?R \<and> N = M + {#a#}) \<or>
wenzelm@10249
   523
          (\<exists>K. (\<forall>b. b :# K --> (b, a) \<in> r) \<and> N = M0 + K))"
wenzelm@10249
   524
        by (rule less_add)
wenzelm@10249
   525
      thus "N \<in> ?W"
wenzelm@10249
   526
      proof (elim exE disjE conjE)
wenzelm@10249
   527
        fix M assume "(M, M0) \<in> ?R" and N: "N = M + {#a#}"
wenzelm@10249
   528
        from acc_hyp have "(M, M0) \<in> ?R --> M + {#a#} \<in> ?W" ..
wenzelm@10249
   529
        hence "M + {#a#} \<in> ?W" ..
wenzelm@10249
   530
        thus "N \<in> ?W" by (simp only: N)
wenzelm@10249
   531
      next
wenzelm@10249
   532
        fix K
wenzelm@10249
   533
        assume N: "N = M0 + K"
wenzelm@10249
   534
        assume "\<forall>b. b :# K --> (b, a) \<in> r"
wenzelm@10249
   535
        have "?this --> M0 + K \<in> ?W" (is "?P K")
wenzelm@10249
   536
        proof (induct K)
wenzelm@10249
   537
          from M0 have "M0 + {#} \<in> ?W" by simp
wenzelm@10249
   538
          thus "?P {#}" ..
wenzelm@10249
   539
wenzelm@10249
   540
          fix K x assume hyp: "?P K"
wenzelm@10249
   541
          show "?P (K + {#x#})"
wenzelm@10249
   542
          proof
wenzelm@10249
   543
            assume a: "\<forall>b. b :# (K + {#x#}) --> (b, a) \<in> r"
wenzelm@10249
   544
            hence "(x, a) \<in> r" by simp
wenzelm@10249
   545
            with wf_hyp have b: "\<forall>M \<in> ?W. M + {#x#} \<in> ?W" by blast
wenzelm@10249
   546
wenzelm@10249
   547
            from a hyp have "M0 + K \<in> ?W" by simp
wenzelm@10249
   548
            with b have "(M0 + K) + {#x#} \<in> ?W" ..
wenzelm@10249
   549
            thus "M0 + (K + {#x#}) \<in> ?W" by (simp only: union_assoc)
wenzelm@10249
   550
          qed
wenzelm@10249
   551
        qed
wenzelm@10249
   552
        hence "M0 + K \<in> ?W" ..
wenzelm@10249
   553
        thus "N \<in> ?W" by (simp only: N)
wenzelm@10249
   554
      qed
wenzelm@10249
   555
    qed
wenzelm@10249
   556
  } note tedious_reasoning = this
wenzelm@10249
   557
wenzelm@10249
   558
  assume wf: "wf r"
wenzelm@10249
   559
  fix M
wenzelm@10249
   560
  show "M \<in> ?W"
wenzelm@10249
   561
  proof (induct M)
wenzelm@10249
   562
    show "{#} \<in> ?W"
wenzelm@10249
   563
    proof (rule accI)
wenzelm@10249
   564
      fix b assume "(b, {#}) \<in> ?R"
wenzelm@10249
   565
      with not_less_empty show "b \<in> ?W" by contradiction
wenzelm@10249
   566
    qed
wenzelm@10249
   567
wenzelm@10249
   568
    fix M a assume "M \<in> ?W"
wenzelm@10249
   569
    from wf have "\<forall>M \<in> ?W. M + {#a#} \<in> ?W"
wenzelm@10249
   570
    proof induct
wenzelm@10249
   571
      fix a
wenzelm@10249
   572
      assume "\<forall>b. (b, a) \<in> r --> (\<forall>M \<in> ?W. M + {#b#} \<in> ?W)"
wenzelm@10249
   573
      show "\<forall>M \<in> ?W. M + {#a#} \<in> ?W"
wenzelm@10249
   574
      proof
wenzelm@10249
   575
        fix M assume "M \<in> ?W"
wenzelm@10249
   576
        thus "M + {#a#} \<in> ?W"
wenzelm@10249
   577
          by (rule acc_induct) (rule tedious_reasoning)
wenzelm@10249
   578
      qed
wenzelm@10249
   579
    qed
wenzelm@10249
   580
    thus "M + {#a#} \<in> ?W" ..
wenzelm@10249
   581
  qed
wenzelm@10249
   582
qed
wenzelm@10249
   583
wenzelm@10249
   584
theorem wf_mult1: "wf r ==> wf (mult1 r)"
wenzelm@10249
   585
  by (rule acc_wfI, rule all_accessible)
wenzelm@10249
   586
wenzelm@10249
   587
theorem wf_mult: "wf r ==> wf (mult r)"
wenzelm@10249
   588
  by (unfold mult_def, rule wf_trancl, rule wf_mult1)
wenzelm@10249
   589
wenzelm@10249
   590
wenzelm@10249
   591
subsubsection {* Closure-free presentation *}
wenzelm@10249
   592
wenzelm@10249
   593
(*Badly needed: a linear arithmetic procedure for multisets*)
wenzelm@10249
   594
wenzelm@10249
   595
lemma diff_union_single_conv: "a :# J ==> I + J - {#a#} = I + (J - {#a#})"
wenzelm@10249
   596
  apply (simp add: multiset_eq_conv_count_eq)
wenzelm@10249
   597
  done
wenzelm@10249
   598
wenzelm@10249
   599
text {* One direction. *}
wenzelm@10249
   600
wenzelm@10249
   601
lemma mult_implies_one_step:
wenzelm@10249
   602
  "trans r ==> (M, N) \<in> mult r ==>
wenzelm@10249
   603
    \<exists>I J K. N = I + J \<and> M = I + K \<and> J \<noteq> {#} \<and>
wenzelm@10249
   604
    (\<forall>k \<in> set_of K. \<exists>j \<in> set_of J. (k, j) \<in> r)"
wenzelm@10249
   605
  apply (unfold mult_def mult1_def set_of_def)
wenzelm@10249
   606
  apply (erule converse_trancl_induct)
wenzelm@10249
   607
  apply clarify
wenzelm@10249
   608
   apply (rule_tac x = M0 in exI)
wenzelm@10249
   609
   apply simp
wenzelm@10249
   610
  apply clarify
wenzelm@10249
   611
  apply (case_tac "a :# K")
wenzelm@10249
   612
   apply (rule_tac x = I in exI)
wenzelm@10249
   613
   apply (simp (no_asm))
wenzelm@10249
   614
   apply (rule_tac x = "(K - {#a#}) + Ka" in exI)
wenzelm@10249
   615
   apply (simp (no_asm_simp) add: union_assoc [symmetric])
wenzelm@10249
   616
   apply (drule_tac f = "\<lambda>M. M - {#a#}" in arg_cong)
wenzelm@10249
   617
   apply (simp add: diff_union_single_conv)
wenzelm@10249
   618
   apply (simp (no_asm_use) add: trans_def)
wenzelm@10249
   619
   apply blast
wenzelm@10249
   620
  apply (subgoal_tac "a :# I")
wenzelm@10249
   621
   apply (rule_tac x = "I - {#a#}" in exI)
wenzelm@10249
   622
   apply (rule_tac x = "J + {#a#}" in exI)
wenzelm@10249
   623
   apply (rule_tac x = "K + Ka" in exI)
wenzelm@10249
   624
   apply (rule conjI)
wenzelm@10249
   625
    apply (simp add: multiset_eq_conv_count_eq split: nat_diff_split)
wenzelm@10249
   626
   apply (rule conjI)
wenzelm@10249
   627
    apply (drule_tac f = "\<lambda>M. M - {#a#}" in arg_cong)
wenzelm@10249
   628
    apply simp
wenzelm@10249
   629
    apply (simp add: multiset_eq_conv_count_eq split: nat_diff_split)
wenzelm@10249
   630
   apply (simp (no_asm_use) add: trans_def)
wenzelm@10249
   631
   apply blast
wenzelm@10249
   632
  apply (subgoal_tac "a :# (M0 +{#a#})")
wenzelm@10249
   633
   apply simp
wenzelm@10249
   634
  apply (simp (no_asm))
wenzelm@10249
   635
  done
wenzelm@10249
   636
wenzelm@10249
   637
lemma elem_imp_eq_diff_union: "a :# M ==> M = M - {#a#} + {#a#}"
wenzelm@10249
   638
  apply (simp add: multiset_eq_conv_count_eq)
wenzelm@10249
   639
  done
wenzelm@10249
   640
wenzelm@10249
   641
lemma size_eq_Suc_imp_eq_union: "size M = Suc n ==> \<exists>a N. M = N + {#a#}"
wenzelm@10249
   642
  apply (erule size_eq_Suc_imp_elem [THEN exE])
wenzelm@10249
   643
  apply (drule elem_imp_eq_diff_union)
wenzelm@10249
   644
  apply auto
wenzelm@10249
   645
  done
wenzelm@10249
   646
wenzelm@10249
   647
lemma one_step_implies_mult_aux:
wenzelm@10249
   648
  "trans r ==>
wenzelm@10249
   649
    \<forall>I J K. (size J = n \<and> J \<noteq> {#} \<and> (\<forall>k \<in> set_of K. \<exists>j \<in> set_of J. (k, j) \<in> r))
wenzelm@10249
   650
      --> (I + K, I + J) \<in> mult r"
wenzelm@10249
   651
  apply (induct_tac n)
wenzelm@10249
   652
   apply auto
wenzelm@10249
   653
  apply (frule size_eq_Suc_imp_eq_union)
wenzelm@10249
   654
  apply clarify
wenzelm@10249
   655
  apply (rename_tac "J'")
wenzelm@10249
   656
  apply simp
wenzelm@10249
   657
  apply (erule notE)
wenzelm@10249
   658
   apply auto
wenzelm@10249
   659
  apply (case_tac "J' = {#}")
wenzelm@10249
   660
   apply (simp add: mult_def)
wenzelm@10249
   661
   apply (rule r_into_trancl)
wenzelm@10249
   662
   apply (simp add: mult1_def set_of_def)
wenzelm@10249
   663
   apply blast
wenzelm@10249
   664
  txt {* Now we know @{term "J' \<noteq> {#}"}. *}
wenzelm@10249
   665
  apply (cut_tac M = K and P = "\<lambda>x. (x, a) \<in> r" in multiset_partition)
wenzelm@10249
   666
  apply (erule_tac P = "\<forall>k \<in> set_of K. ?P k" in rev_mp)
wenzelm@10249
   667
  apply (erule ssubst)
wenzelm@10249
   668
  apply (simp add: Ball_def)
wenzelm@10249
   669
  apply auto
wenzelm@10249
   670
  apply (subgoal_tac
wenzelm@10249
   671
    "((I + {# x : K. (x, a) \<in> r #}) + {# x : K. (x, a) \<notin> r #},
wenzelm@10249
   672
      (I + {# x : K. (x, a) \<in> r #}) + J') \<in> mult r")
wenzelm@10249
   673
   prefer 2
wenzelm@10249
   674
   apply force
wenzelm@10249
   675
  apply (simp (no_asm_use) add: union_assoc [symmetric] mult_def)
wenzelm@10249
   676
  apply (erule trancl_trans)
wenzelm@10249
   677
  apply (rule r_into_trancl)
wenzelm@10249
   678
  apply (simp add: mult1_def set_of_def)
wenzelm@10249
   679
  apply (rule_tac x = a in exI)
wenzelm@10249
   680
  apply (rule_tac x = "I + J'" in exI)
wenzelm@10249
   681
  apply (simp add: union_ac)
wenzelm@10249
   682
  done
wenzelm@10249
   683
wenzelm@10249
   684
theorem one_step_implies_mult:
wenzelm@10249
   685
  "trans r ==> J \<noteq> {#} ==> \<forall>k \<in> set_of K. \<exists>j \<in> set_of J. (k, j) \<in> r
wenzelm@10249
   686
    ==> (I + K, I + J) \<in> mult r"
wenzelm@10249
   687
  apply (insert one_step_implies_mult_aux)
wenzelm@10249
   688
  apply blast
wenzelm@10249
   689
  done
wenzelm@10249
   690
wenzelm@10249
   691
wenzelm@10249
   692
subsubsection {* Partial-order properties *}
wenzelm@10249
   693
wenzelm@10249
   694
instance multiset :: ("term") ord by intro_classes
wenzelm@10249
   695
wenzelm@10249
   696
defs (overloaded)
wenzelm@10249
   697
  less_multiset_def: "M' < M == (M', M) \<in> mult {(x', x). x' < x}"
wenzelm@10249
   698
  le_multiset_def: "M' <= M == M' = M \<or> M' < (M::'a multiset)"
wenzelm@10249
   699
wenzelm@10249
   700
lemma trans_base_order: "trans {(x', x). x' < (x::'a::order)}"
wenzelm@10249
   701
  apply (unfold trans_def)
wenzelm@10249
   702
  apply (blast intro: order_less_trans)
wenzelm@10249
   703
  done
wenzelm@10249
   704
wenzelm@10249
   705
text {*
wenzelm@10249
   706
 \medskip Irreflexivity.
wenzelm@10249
   707
*}
wenzelm@10249
   708
wenzelm@10249
   709
lemma mult_irrefl_aux:
wenzelm@10249
   710
    "finite A ==> (\<forall>x \<in> A. \<exists>y \<in> A. x < (y::'a::order)) --> A = {}"
wenzelm@10249
   711
  apply (erule finite_induct)
wenzelm@10249
   712
   apply (auto intro: order_less_trans)
wenzelm@10249
   713
  done
wenzelm@10249
   714
wenzelm@10249
   715
theorem mult_less_not_refl: "\<not> M < (M::'a::order multiset)"
wenzelm@10249
   716
  apply (unfold less_multiset_def)
wenzelm@10249
   717
  apply auto
wenzelm@10249
   718
  apply (drule trans_base_order [THEN mult_implies_one_step])
wenzelm@10249
   719
  apply auto
wenzelm@10249
   720
  apply (drule finite_set_of [THEN mult_irrefl_aux [rule_format (no_asm)]])
wenzelm@10249
   721
  apply (simp add: set_of_eq_empty_iff)
wenzelm@10249
   722
  done
wenzelm@10249
   723
wenzelm@10249
   724
lemma mult_less_irrefl [elim!]: "M < (M::'a::order multiset) ==> R"
wenzelm@10249
   725
  apply (insert mult_less_not_refl)
wenzelm@10249
   726
  apply blast
wenzelm@10249
   727
  done
wenzelm@10249
   728
wenzelm@10249
   729
wenzelm@10249
   730
text {* Transitivity. *}
wenzelm@10249
   731
wenzelm@10249
   732
theorem mult_less_trans: "K < M ==> M < N ==> K < (N::'a::order multiset)"
wenzelm@10249
   733
  apply (unfold less_multiset_def mult_def)
wenzelm@10249
   734
  apply (blast intro: trancl_trans)
wenzelm@10249
   735
  done
wenzelm@10249
   736
wenzelm@10249
   737
text {* Asymmetry. *}
wenzelm@10249
   738
wenzelm@10249
   739
theorem mult_less_not_sym: "M < N ==> \<not> N < (M::'a::order multiset)"
wenzelm@10249
   740
  apply auto
wenzelm@10249
   741
  apply (rule mult_less_not_refl [THEN notE])
wenzelm@10249
   742
  apply (erule mult_less_trans)
wenzelm@10249
   743
  apply assumption
wenzelm@10249
   744
  done
wenzelm@10249
   745
wenzelm@10249
   746
theorem mult_less_asym:
wenzelm@10249
   747
    "M < N ==> (\<not> P ==> N < (M::'a::order multiset)) ==> P"
wenzelm@10249
   748
  apply (insert mult_less_not_sym)
wenzelm@10249
   749
  apply blast
wenzelm@10249
   750
  done
wenzelm@10249
   751
wenzelm@10249
   752
theorem mult_le_refl [iff]: "M <= (M::'a::order multiset)"
wenzelm@10249
   753
  apply (unfold le_multiset_def)
wenzelm@10249
   754
  apply auto
wenzelm@10249
   755
  done
wenzelm@10249
   756
wenzelm@10249
   757
text {* Anti-symmetry. *}
wenzelm@10249
   758
wenzelm@10249
   759
theorem mult_le_antisym:
wenzelm@10249
   760
    "M <= N ==> N <= M ==> M = (N::'a::order multiset)"
wenzelm@10249
   761
  apply (unfold le_multiset_def)
wenzelm@10249
   762
  apply (blast dest: mult_less_not_sym)
wenzelm@10249
   763
  done
wenzelm@10249
   764
wenzelm@10249
   765
text {* Transitivity. *}
wenzelm@10249
   766
wenzelm@10249
   767
theorem mult_le_trans:
wenzelm@10249
   768
    "K <= M ==> M <= N ==> K <= (N::'a::order multiset)"
wenzelm@10249
   769
  apply (unfold le_multiset_def)
wenzelm@10249
   770
  apply (blast intro: mult_less_trans)
wenzelm@10249
   771
  done
wenzelm@10249
   772
wenzelm@10249
   773
theorem mult_less_le: "M < N = (M <= N \<and> M \<noteq> (N::'a::order multiset))"
wenzelm@10249
   774
  apply (unfold le_multiset_def)
wenzelm@10249
   775
  apply auto
wenzelm@10249
   776
  done
wenzelm@10249
   777
wenzelm@10249
   778
wenzelm@10249
   779
subsubsection {* Monotonicity of multiset union *}
wenzelm@10249
   780
wenzelm@10249
   781
theorem mult1_union:
wenzelm@10249
   782
    "(B, D) \<in> mult1 r ==> trans r ==> (C + B, C + D) \<in> mult1 r"
wenzelm@10249
   783
  apply (unfold mult1_def)
wenzelm@10249
   784
  apply auto
wenzelm@10249
   785
  apply (rule_tac x = a in exI)
wenzelm@10249
   786
  apply (rule_tac x = "C + M0" in exI)
wenzelm@10249
   787
  apply (simp add: union_assoc)
wenzelm@10249
   788
  done
wenzelm@10249
   789
wenzelm@10249
   790
lemma union_less_mono2: "B < D ==> C + B < C + (D::'a::order multiset)"
wenzelm@10249
   791
  apply (unfold less_multiset_def mult_def)
wenzelm@10249
   792
  apply (erule trancl_induct)
wenzelm@10249
   793
   apply (blast intro: mult1_union transI order_less_trans r_into_trancl)
wenzelm@10249
   794
  apply (blast intro: mult1_union transI order_less_trans r_into_trancl trancl_trans)
wenzelm@10249
   795
  done
wenzelm@10249
   796
wenzelm@10249
   797
lemma union_less_mono1: "B < D ==> B + C < D + (C::'a::order multiset)"
wenzelm@10249
   798
  apply (subst union_commute [of B C])
wenzelm@10249
   799
  apply (subst union_commute [of D C])
wenzelm@10249
   800
  apply (erule union_less_mono2)
wenzelm@10249
   801
  done
wenzelm@10249
   802
wenzelm@10249
   803
theorem union_less_mono:
wenzelm@10249
   804
    "A < C ==> B < D ==> A + B < C + (D::'a::order multiset)"
wenzelm@10249
   805
  apply (blast intro!: union_less_mono1 union_less_mono2 mult_less_trans)
wenzelm@10249
   806
  done
wenzelm@10249
   807
wenzelm@10249
   808
theorem union_le_mono:
wenzelm@10249
   809
    "A <= C ==> B <= D ==> A + B <= C + (D::'a::order multiset)"
wenzelm@10249
   810
  apply (unfold le_multiset_def)
wenzelm@10249
   811
  apply (blast intro: union_less_mono union_less_mono1 union_less_mono2)
wenzelm@10249
   812
  done
wenzelm@10249
   813
wenzelm@10249
   814
theorem empty_leI [iff]: "{#} <= (M::'a::order multiset)"
wenzelm@10249
   815
  apply (unfold le_multiset_def less_multiset_def)
wenzelm@10249
   816
  apply (case_tac "M = {#}")
wenzelm@10249
   817
   prefer 2
wenzelm@10249
   818
   apply (subgoal_tac "({#} + {#}, {#} + M) \<in> mult (Collect (split op <))")
wenzelm@10249
   819
    prefer 2
wenzelm@10249
   820
    apply (rule one_step_implies_mult)
wenzelm@10249
   821
      apply (simp only: trans_def)
wenzelm@10249
   822
      apply auto
wenzelm@10249
   823
  apply (blast intro: order_less_trans)
wenzelm@10249
   824
  done
wenzelm@10249
   825
wenzelm@10249
   826
theorem union_upper1: "A <= A + (B::'a::order multiset)"
wenzelm@10249
   827
  apply (subgoal_tac "A + {#} <= A + B")
wenzelm@10249
   828
   prefer 2
wenzelm@10249
   829
   apply (rule union_le_mono)
wenzelm@10249
   830
    apply auto
wenzelm@10249
   831
  done
wenzelm@10249
   832
wenzelm@10249
   833
theorem union_upper2: "B <= A + (B::'a::order multiset)"
wenzelm@10249
   834
  apply (subst union_commute, rule union_upper1)
wenzelm@10249
   835
  done
wenzelm@10249
   836
wenzelm@10249
   837
instance multiset :: (order) order
wenzelm@10249
   838
  apply intro_classes
wenzelm@10249
   839
     apply (rule mult_le_refl)
wenzelm@10249
   840
    apply (erule mult_le_trans)
wenzelm@10249
   841
    apply assumption
wenzelm@10249
   842
   apply (erule mult_le_antisym)
wenzelm@10249
   843
   apply assumption
wenzelm@10249
   844
  apply (rule mult_less_le)
wenzelm@10249
   845
  done
wenzelm@10249
   846
wenzelm@10249
   847
instance multiset :: ("term") plus_ac0
wenzelm@10249
   848
  apply intro_classes
wenzelm@10249
   849
    apply (rule union_commute)
wenzelm@10249
   850
   apply (rule union_assoc)
wenzelm@10249
   851
  apply simp
wenzelm@10249
   852
  done
wenzelm@10249
   853
wenzelm@10249
   854
end