src/HOL/Relation.thy
author hoelzl
Fri Feb 19 13:40:50 2016 +0100 (2016-02-19)
changeset 62378 85ed00c1fe7c
parent 62343 24106dc44def
child 63376 4c0cc2b356f0
permissions -rw-r--r--
generalize more theorems to support enat and ennreal
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(*  Title:      HOL/Relation.thy
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    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory; Stefan Berghofer, TU Muenchen
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*)
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section \<open>Relations -- as sets of pairs, and binary predicates\<close>
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theory Relation
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imports Finite_Set
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begin
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text \<open>A preliminary: classical rules for reasoning on predicates\<close>
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declare predicate1I [Pure.intro!, intro!]
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declare predicate1D [Pure.dest, dest]
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declare predicate2I [Pure.intro!, intro!]
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declare predicate2D [Pure.dest, dest]
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declare bot1E [elim!] 
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declare bot2E [elim!]
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declare top1I [intro!]
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declare top2I [intro!]
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declare inf1I [intro!]
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declare inf2I [intro!]
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declare inf1E [elim!]
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declare inf2E [elim!]
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declare sup1I1 [intro?]
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declare sup2I1 [intro?]
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declare sup1I2 [intro?]
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declare sup2I2 [intro?]
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declare sup1E [elim!]
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declare sup2E [elim!]
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declare sup1CI [intro!]
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declare sup2CI [intro!]
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declare Inf1_I [intro!]
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declare INF1_I [intro!]
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declare Inf2_I [intro!]
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declare INF2_I [intro!]
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declare Inf1_D [elim]
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declare INF1_D [elim]
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declare Inf2_D [elim]
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declare INF2_D [elim]
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declare Inf1_E [elim]
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declare INF1_E [elim]
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declare Inf2_E [elim]
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declare INF2_E [elim]
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declare Sup1_I [intro]
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declare SUP1_I [intro]
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declare Sup2_I [intro]
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declare SUP2_I [intro]
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declare Sup1_E [elim!]
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declare SUP1_E [elim!]
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declare Sup2_E [elim!]
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declare SUP2_E [elim!]
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subsection \<open>Fundamental\<close>
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subsubsection \<open>Relations as sets of pairs\<close>
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type_synonym 'a rel = "('a * 'a) set"
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lemma subrelI: \<comment> \<open>Version of @{thm [source] subsetI} for binary relations\<close>
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  "(\<And>x y. (x, y) \<in> r \<Longrightarrow> (x, y) \<in> s) \<Longrightarrow> r \<subseteq> s"
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  by auto
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lemma lfp_induct2: \<comment> \<open>Version of @{thm [source] lfp_induct} for binary relations\<close>
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  "(a, b) \<in> lfp f \<Longrightarrow> mono f \<Longrightarrow>
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    (\<And>a b. (a, b) \<in> f (lfp f \<inter> {(x, y). P x y}) \<Longrightarrow> P a b) \<Longrightarrow> P a b"
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  using lfp_induct_set [of "(a, b)" f "case_prod P"] by auto
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subsubsection \<open>Conversions between set and predicate relations\<close>
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lemma pred_equals_eq [pred_set_conv]: "(\<lambda>x. x \<in> R) = (\<lambda>x. x \<in> S) \<longleftrightarrow> R = S"
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  by (simp add: set_eq_iff fun_eq_iff)
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lemma pred_equals_eq2 [pred_set_conv]: "(\<lambda>x y. (x, y) \<in> R) = (\<lambda>x y. (x, y) \<in> S) \<longleftrightarrow> R = S"
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  by (simp add: set_eq_iff fun_eq_iff)
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lemma pred_subset_eq [pred_set_conv]: "(\<lambda>x. x \<in> R) \<le> (\<lambda>x. x \<in> S) \<longleftrightarrow> R \<subseteq> S"
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  by (simp add: subset_iff le_fun_def)
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lemma pred_subset_eq2 [pred_set_conv]: "(\<lambda>x y. (x, y) \<in> R) \<le> (\<lambda>x y. (x, y) \<in> S) \<longleftrightarrow> R \<subseteq> S"
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  by (simp add: subset_iff le_fun_def)
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lemma bot_empty_eq [pred_set_conv]: "\<bottom> = (\<lambda>x. x \<in> {})"
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  by (auto simp add: fun_eq_iff)
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lemma bot_empty_eq2 [pred_set_conv]: "\<bottom> = (\<lambda>x y. (x, y) \<in> {})"
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  by (auto simp add: fun_eq_iff)
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lemma top_empty_eq [pred_set_conv]: "\<top> = (\<lambda>x. x \<in> UNIV)"
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  by (auto simp add: fun_eq_iff)
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lemma top_empty_eq2 [pred_set_conv]: "\<top> = (\<lambda>x y. (x, y) \<in> UNIV)"
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  by (auto simp add: fun_eq_iff)
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lemma inf_Int_eq [pred_set_conv]: "(\<lambda>x. x \<in> R) \<sqinter> (\<lambda>x. x \<in> S) = (\<lambda>x. x \<in> R \<inter> S)"
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  by (simp add: inf_fun_def)
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lemma inf_Int_eq2 [pred_set_conv]: "(\<lambda>x y. (x, y) \<in> R) \<sqinter> (\<lambda>x y. (x, y) \<in> S) = (\<lambda>x y. (x, y) \<in> R \<inter> S)"
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  by (simp add: inf_fun_def)
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lemma sup_Un_eq [pred_set_conv]: "(\<lambda>x. x \<in> R) \<squnion> (\<lambda>x. x \<in> S) = (\<lambda>x. x \<in> R \<union> S)"
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  by (simp add: sup_fun_def)
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lemma sup_Un_eq2 [pred_set_conv]: "(\<lambda>x y. (x, y) \<in> R) \<squnion> (\<lambda>x y. (x, y) \<in> S) = (\<lambda>x y. (x, y) \<in> R \<union> S)"
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  by (simp add: sup_fun_def)
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lemma INF_INT_eq [pred_set_conv]: "(\<Sqinter>i\<in>S. (\<lambda>x. x \<in> r i)) = (\<lambda>x. x \<in> (\<Inter>i\<in>S. r i))"
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  by (simp add: fun_eq_iff)
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lemma INF_INT_eq2 [pred_set_conv]: "(\<Sqinter>i\<in>S. (\<lambda>x y. (x, y) \<in> r i)) = (\<lambda>x y. (x, y) \<in> (\<Inter>i\<in>S. r i))"
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  by (simp add: fun_eq_iff)
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lemma SUP_UN_eq [pred_set_conv]: "(\<Squnion>i\<in>S. (\<lambda>x. x \<in> r i)) = (\<lambda>x. x \<in> (\<Union>i\<in>S. r i))"
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  by (simp add: fun_eq_iff)
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lemma SUP_UN_eq2 [pred_set_conv]: "(\<Squnion>i\<in>S. (\<lambda>x y. (x, y) \<in> r i)) = (\<lambda>x y. (x, y) \<in> (\<Union>i\<in>S. r i))"
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  by (simp add: fun_eq_iff)
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lemma Inf_INT_eq [pred_set_conv]: "\<Sqinter>S = (\<lambda>x. x \<in> INTER S Collect)"
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  by (simp add: fun_eq_iff)
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lemma INF_Int_eq [pred_set_conv]: "(\<Sqinter>i\<in>S. (\<lambda>x. x \<in> i)) = (\<lambda>x. x \<in> \<Inter>S)"
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  by (simp add: fun_eq_iff)
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lemma Inf_INT_eq2 [pred_set_conv]: "\<Sqinter>S = (\<lambda>x y. (x, y) \<in> INTER (case_prod ` S) Collect)"
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  by (simp add: fun_eq_iff)
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lemma INF_Int_eq2 [pred_set_conv]: "(\<Sqinter>i\<in>S. (\<lambda>x y. (x, y) \<in> i)) = (\<lambda>x y. (x, y) \<in> \<Inter>S)"
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  by (simp add: fun_eq_iff)
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lemma Sup_SUP_eq [pred_set_conv]: "\<Squnion>S = (\<lambda>x. x \<in> UNION S Collect)"
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  by (simp add: fun_eq_iff)
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lemma SUP_Sup_eq [pred_set_conv]: "(\<Squnion>i\<in>S. (\<lambda>x. x \<in> i)) = (\<lambda>x. x \<in> \<Union>S)"
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  by (simp add: fun_eq_iff)
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lemma Sup_SUP_eq2 [pred_set_conv]: "\<Squnion>S = (\<lambda>x y. (x, y) \<in> UNION (case_prod ` S) Collect)"
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  by (simp add: fun_eq_iff)
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lemma SUP_Sup_eq2 [pred_set_conv]: "(\<Squnion>i\<in>S. (\<lambda>x y. (x, y) \<in> i)) = (\<lambda>x y. (x, y) \<in> \<Union>S)"
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  by (simp add: fun_eq_iff)
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subsection \<open>Properties of relations\<close>
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subsubsection \<open>Reflexivity\<close>
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definition refl_on :: "'a set \<Rightarrow> 'a rel \<Rightarrow> bool"
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where
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  "refl_on A r \<longleftrightarrow> r \<subseteq> A \<times> A \<and> (\<forall>x\<in>A. (x, x) \<in> r)"
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abbreviation refl :: "'a rel \<Rightarrow> bool"
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where \<comment> \<open>reflexivity over a type\<close>
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  "refl \<equiv> refl_on UNIV"
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definition reflp :: "('a \<Rightarrow> 'a \<Rightarrow> bool) \<Rightarrow> bool"
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where
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  "reflp r \<longleftrightarrow> (\<forall>x. r x x)"
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lemma reflp_refl_eq [pred_set_conv]:
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  "reflp (\<lambda>x y. (x, y) \<in> r) \<longleftrightarrow> refl r" 
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  by (simp add: refl_on_def reflp_def)
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lemma refl_onI: "r \<subseteq> A \<times> A ==> (!!x. x : A ==> (x, x) : r) ==> refl_on A r"
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  by (unfold refl_on_def) (iprover intro!: ballI)
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lemma refl_onD: "refl_on A r ==> a : A ==> (a, a) : r"
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  by (unfold refl_on_def) blast
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lemma refl_onD1: "refl_on A r ==> (x, y) : r ==> x : A"
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  by (unfold refl_on_def) blast
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lemma refl_onD2: "refl_on A r ==> (x, y) : r ==> y : A"
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  by (unfold refl_on_def) blast
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lemma reflpI:
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  "(\<And>x. r x x) \<Longrightarrow> reflp r"
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  by (auto intro: refl_onI simp add: reflp_def)
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lemma reflpE:
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  assumes "reflp r"
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  obtains "r x x"
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  using assms by (auto dest: refl_onD simp add: reflp_def)
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lemma reflpD:
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  assumes "reflp r"
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  shows "r x x"
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  using assms by (auto elim: reflpE)
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lemma refl_on_Int: "refl_on A r ==> refl_on B s ==> refl_on (A \<inter> B) (r \<inter> s)"
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  by (unfold refl_on_def) blast
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lemma reflp_inf:
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  "reflp r \<Longrightarrow> reflp s \<Longrightarrow> reflp (r \<sqinter> s)"
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  by (auto intro: reflpI elim: reflpE)
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lemma refl_on_Un: "refl_on A r ==> refl_on B s ==> refl_on (A \<union> B) (r \<union> s)"
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  by (unfold refl_on_def) blast
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lemma reflp_sup:
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  "reflp r \<Longrightarrow> reflp s \<Longrightarrow> reflp (r \<squnion> s)"
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  by (auto intro: reflpI elim: reflpE)
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lemma refl_on_INTER:
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  "ALL x:S. refl_on (A x) (r x) ==> refl_on (INTER S A) (INTER S r)"
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  by (unfold refl_on_def) fast
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lemma refl_on_UNION:
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  "ALL x:S. refl_on (A x) (r x) \<Longrightarrow> refl_on (UNION S A) (UNION S r)"
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  by (unfold refl_on_def) blast
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lemma refl_on_empty [simp]: "refl_on {} {}"
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  by (simp add:refl_on_def)
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lemma refl_on_def' [nitpick_unfold, code]:
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  "refl_on A r \<longleftrightarrow> (\<forall>(x, y) \<in> r. x \<in> A \<and> y \<in> A) \<and> (\<forall>x \<in> A. (x, x) \<in> r)"
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  by (auto intro: refl_onI dest: refl_onD refl_onD1 refl_onD2)
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lemma reflp_equality [simp]: "reflp op ="
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by(simp add: reflp_def)
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lemma reflp_mono: "\<lbrakk> reflp R; \<And>x y. R x y \<longrightarrow> Q x y \<rbrakk> \<Longrightarrow> reflp Q"
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by(auto intro: reflpI dest: reflpD)
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subsubsection \<open>Irreflexivity\<close>
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definition irrefl :: "'a rel \<Rightarrow> bool"
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where
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  "irrefl r \<longleftrightarrow> (\<forall>a. (a, a) \<notin> r)"
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definition irreflp :: "('a \<Rightarrow> 'a \<Rightarrow> bool) \<Rightarrow> bool"
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where
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  "irreflp R \<longleftrightarrow> (\<forall>a. \<not> R a a)"
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lemma irreflp_irrefl_eq [pred_set_conv]:
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  "irreflp (\<lambda>a b. (a, b) \<in> R) \<longleftrightarrow> irrefl R" 
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  by (simp add: irrefl_def irreflp_def)
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lemma irreflI:
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  "(\<And>a. (a, a) \<notin> R) \<Longrightarrow> irrefl R"
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  by (simp add: irrefl_def)
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lemma irreflpI:
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  "(\<And>a. \<not> R a a) \<Longrightarrow> irreflp R"
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  by (fact irreflI [to_pred])
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lemma irrefl_distinct [code]:
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  "irrefl r \<longleftrightarrow> (\<forall>(a, b) \<in> r. a \<noteq> b)"
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  by (auto simp add: irrefl_def)
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subsubsection \<open>Asymmetry\<close>
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inductive asym :: "'a rel \<Rightarrow> bool"
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where
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  asymI: "irrefl R \<Longrightarrow> (\<And>a b. (a, b) \<in> R \<Longrightarrow> (b, a) \<notin> R) \<Longrightarrow> asym R"
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inductive asymp :: "('a \<Rightarrow> 'a \<Rightarrow> bool) \<Rightarrow> bool"
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where
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  asympI: "irreflp R \<Longrightarrow> (\<And>a b. R a b \<Longrightarrow> \<not> R b a) \<Longrightarrow> asymp R"
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lemma asymp_asym_eq [pred_set_conv]:
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  "asymp (\<lambda>a b. (a, b) \<in> R) \<longleftrightarrow> asym R" 
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  by (auto intro!: asymI asympI elim: asym.cases asymp.cases simp add: irreflp_irrefl_eq)
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subsubsection \<open>Symmetry\<close>
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definition sym :: "'a rel \<Rightarrow> bool"
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where
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  "sym r \<longleftrightarrow> (\<forall>x y. (x, y) \<in> r \<longrightarrow> (y, x) \<in> r)"
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definition symp :: "('a \<Rightarrow> 'a \<Rightarrow> bool) \<Rightarrow> bool"
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where
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  "symp r \<longleftrightarrow> (\<forall>x y. r x y \<longrightarrow> r y x)"
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lemma symp_sym_eq [pred_set_conv]:
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  "symp (\<lambda>x y. (x, y) \<in> r) \<longleftrightarrow> sym r" 
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  by (simp add: sym_def symp_def)
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lemma symI:
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  "(\<And>a b. (a, b) \<in> r \<Longrightarrow> (b, a) \<in> r) \<Longrightarrow> sym r"
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  by (unfold sym_def) iprover
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lemma sympI:
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  "(\<And>a b. r a b \<Longrightarrow> r b a) \<Longrightarrow> symp r"
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  by (fact symI [to_pred])
haftmann@46752
   288
haftmann@46752
   289
lemma symE:
haftmann@46752
   290
  assumes "sym r" and "(b, a) \<in> r"
haftmann@46752
   291
  obtains "(a, b) \<in> r"
haftmann@46752
   292
  using assms by (simp add: sym_def)
haftmann@46694
   293
haftmann@46694
   294
lemma sympE:
haftmann@46752
   295
  assumes "symp r" and "r b a"
haftmann@46752
   296
  obtains "r a b"
haftmann@46752
   297
  using assms by (rule symE [to_pred])
haftmann@46752
   298
haftmann@46752
   299
lemma symD:
haftmann@46752
   300
  assumes "sym r" and "(b, a) \<in> r"
haftmann@46752
   301
  shows "(a, b) \<in> r"
haftmann@46752
   302
  using assms by (rule symE)
haftmann@46694
   303
haftmann@46752
   304
lemma sympD:
haftmann@46752
   305
  assumes "symp r" and "r b a"
haftmann@46752
   306
  shows "r a b"
haftmann@46752
   307
  using assms by (rule symD [to_pred])
haftmann@46752
   308
haftmann@46752
   309
lemma sym_Int:
haftmann@46752
   310
  "sym r \<Longrightarrow> sym s \<Longrightarrow> sym (r \<inter> s)"
haftmann@46752
   311
  by (fast intro: symI elim: symE)
haftmann@46692
   312
haftmann@46752
   313
lemma symp_inf:
haftmann@46752
   314
  "symp r \<Longrightarrow> symp s \<Longrightarrow> symp (r \<sqinter> s)"
haftmann@46752
   315
  by (fact sym_Int [to_pred])
haftmann@46752
   316
haftmann@46752
   317
lemma sym_Un:
haftmann@46752
   318
  "sym r \<Longrightarrow> sym s \<Longrightarrow> sym (r \<union> s)"
haftmann@46752
   319
  by (fast intro: symI elim: symE)
haftmann@46752
   320
haftmann@46752
   321
lemma symp_sup:
haftmann@46752
   322
  "symp r \<Longrightarrow> symp s \<Longrightarrow> symp (r \<squnion> s)"
haftmann@46752
   323
  by (fact sym_Un [to_pred])
haftmann@46692
   324
haftmann@46752
   325
lemma sym_INTER:
haftmann@46752
   326
  "\<forall>x\<in>S. sym (r x) \<Longrightarrow> sym (INTER S r)"
haftmann@46752
   327
  by (fast intro: symI elim: symE)
haftmann@46752
   328
haftmann@46982
   329
lemma symp_INF:
haftmann@56218
   330
  "\<forall>x\<in>S. symp (r x) \<Longrightarrow> symp (INFIMUM S r)"
haftmann@46982
   331
  by (fact sym_INTER [to_pred])
haftmann@46692
   332
haftmann@46752
   333
lemma sym_UNION:
haftmann@46752
   334
  "\<forall>x\<in>S. sym (r x) \<Longrightarrow> sym (UNION S r)"
haftmann@46752
   335
  by (fast intro: symI elim: symE)
haftmann@46752
   336
haftmann@46982
   337
lemma symp_SUP:
haftmann@56218
   338
  "\<forall>x\<in>S. symp (r x) \<Longrightarrow> symp (SUPREMUM S r)"
haftmann@46982
   339
  by (fact sym_UNION [to_pred])
haftmann@46692
   340
haftmann@46692
   341
wenzelm@60758
   342
subsubsection \<open>Antisymmetry\<close>
haftmann@46694
   343
haftmann@46752
   344
definition antisym :: "'a rel \<Rightarrow> bool"
haftmann@46752
   345
where
haftmann@46752
   346
  "antisym r \<longleftrightarrow> (\<forall>x y. (x, y) \<in> r \<longrightarrow> (y, x) \<in> r \<longrightarrow> x = y)"
haftmann@46752
   347
haftmann@46752
   348
abbreviation antisymP :: "('a \<Rightarrow> 'a \<Rightarrow> bool) \<Rightarrow> bool"
haftmann@46752
   349
where
haftmann@46752
   350
  "antisymP r \<equiv> antisym {(x, y). r x y}"
haftmann@46694
   351
haftmann@46694
   352
lemma antisymI:
haftmann@46694
   353
  "(!!x y. (x, y) : r ==> (y, x) : r ==> x=y) ==> antisym r"
haftmann@46752
   354
  by (unfold antisym_def) iprover
haftmann@46694
   355
haftmann@46694
   356
lemma antisymD: "antisym r ==> (a, b) : r ==> (b, a) : r ==> a = b"
haftmann@46752
   357
  by (unfold antisym_def) iprover
haftmann@46694
   358
haftmann@46694
   359
lemma antisym_subset: "r \<subseteq> s ==> antisym s ==> antisym r"
haftmann@46752
   360
  by (unfold antisym_def) blast
haftmann@46694
   361
haftmann@46694
   362
lemma antisym_empty [simp]: "antisym {}"
haftmann@46752
   363
  by (unfold antisym_def) blast
haftmann@46694
   364
Andreas@60057
   365
lemma antisymP_equality [simp]: "antisymP op ="
Andreas@60057
   366
by(auto intro: antisymI)
haftmann@46694
   367
wenzelm@60758
   368
subsubsection \<open>Transitivity\<close>
haftmann@46692
   369
haftmann@46752
   370
definition trans :: "'a rel \<Rightarrow> bool"
haftmann@46752
   371
where
haftmann@46752
   372
  "trans r \<longleftrightarrow> (\<forall>x y z. (x, y) \<in> r \<longrightarrow> (y, z) \<in> r \<longrightarrow> (x, z) \<in> r)"
haftmann@46752
   373
haftmann@46752
   374
definition transp :: "('a \<Rightarrow> 'a \<Rightarrow> bool) \<Rightarrow> bool"
haftmann@46752
   375
where
haftmann@46752
   376
  "transp r \<longleftrightarrow> (\<forall>x y z. r x y \<longrightarrow> r y z \<longrightarrow> r x z)"
haftmann@46752
   377
haftmann@46752
   378
lemma transp_trans_eq [pred_set_conv]:
haftmann@46752
   379
  "transp (\<lambda>x y. (x, y) \<in> r) \<longleftrightarrow> trans r" 
haftmann@46752
   380
  by (simp add: trans_def transp_def)
haftmann@46752
   381
haftmann@46752
   382
abbreviation transP :: "('a \<Rightarrow> 'a \<Rightarrow> bool) \<Rightarrow> bool"
wenzelm@61799
   383
where \<comment> \<open>FIXME drop\<close>
haftmann@46752
   384
  "transP r \<equiv> trans {(x, y). r x y}"
paulson@5978
   385
haftmann@46692
   386
lemma transI:
haftmann@46752
   387
  "(\<And>x y z. (x, y) \<in> r \<Longrightarrow> (y, z) \<in> r \<Longrightarrow> (x, z) \<in> r) \<Longrightarrow> trans r"
haftmann@46752
   388
  by (unfold trans_def) iprover
haftmann@46694
   389
haftmann@46694
   390
lemma transpI:
haftmann@46694
   391
  "(\<And>x y z. r x y \<Longrightarrow> r y z \<Longrightarrow> r x z) \<Longrightarrow> transp r"
haftmann@46752
   392
  by (fact transI [to_pred])
haftmann@46752
   393
haftmann@46752
   394
lemma transE:
haftmann@46752
   395
  assumes "trans r" and "(x, y) \<in> r" and "(y, z) \<in> r"
haftmann@46752
   396
  obtains "(x, z) \<in> r"
haftmann@46752
   397
  using assms by (unfold trans_def) iprover
haftmann@46752
   398
haftmann@46694
   399
lemma transpE:
haftmann@46694
   400
  assumes "transp r" and "r x y" and "r y z"
haftmann@46694
   401
  obtains "r x z"
haftmann@46752
   402
  using assms by (rule transE [to_pred])
haftmann@46752
   403
haftmann@46752
   404
lemma transD:
haftmann@46752
   405
  assumes "trans r" and "(x, y) \<in> r" and "(y, z) \<in> r"
haftmann@46752
   406
  shows "(x, z) \<in> r"
haftmann@46752
   407
  using assms by (rule transE)
haftmann@46752
   408
haftmann@46752
   409
lemma transpD:
haftmann@46752
   410
  assumes "transp r" and "r x y" and "r y z"
haftmann@46752
   411
  shows "r x z"
haftmann@46752
   412
  using assms by (rule transD [to_pred])
haftmann@46694
   413
haftmann@46752
   414
lemma trans_Int:
haftmann@46752
   415
  "trans r \<Longrightarrow> trans s \<Longrightarrow> trans (r \<inter> s)"
haftmann@46752
   416
  by (fast intro: transI elim: transE)
haftmann@46692
   417
haftmann@46752
   418
lemma transp_inf:
haftmann@46752
   419
  "transp r \<Longrightarrow> transp s \<Longrightarrow> transp (r \<sqinter> s)"
haftmann@46752
   420
  by (fact trans_Int [to_pred])
haftmann@46752
   421
haftmann@46752
   422
lemma trans_INTER:
haftmann@46752
   423
  "\<forall>x\<in>S. trans (r x) \<Longrightarrow> trans (INTER S r)"
haftmann@46752
   424
  by (fast intro: transI elim: transD)
haftmann@46752
   425
haftmann@46752
   426
(* FIXME thm trans_INTER [to_pred] *)
haftmann@46692
   427
haftmann@46694
   428
lemma trans_join [code]:
haftmann@46694
   429
  "trans r \<longleftrightarrow> (\<forall>(x, y1) \<in> r. \<forall>(y2, z) \<in> r. y1 = y2 \<longrightarrow> (x, z) \<in> r)"
haftmann@46694
   430
  by (auto simp add: trans_def)
haftmann@46692
   431
haftmann@46752
   432
lemma transp_trans:
haftmann@46752
   433
  "transp r \<longleftrightarrow> trans {(x, y). r x y}"
haftmann@46752
   434
  by (simp add: trans_def transp_def)
haftmann@46752
   435
Andreas@59518
   436
lemma transp_equality [simp]: "transp op ="
Andreas@59518
   437
by(auto intro: transpI)
haftmann@46692
   438
wenzelm@60758
   439
subsubsection \<open>Totality\<close>
haftmann@46692
   440
haftmann@46752
   441
definition total_on :: "'a set \<Rightarrow> 'a rel \<Rightarrow> bool"
haftmann@46752
   442
where
haftmann@46752
   443
  "total_on A r \<longleftrightarrow> (\<forall>x\<in>A. \<forall>y\<in>A. x \<noteq> y \<longrightarrow> (x, y) \<in> r \<or> (y, x) \<in> r)"
nipkow@29859
   444
nipkow@29859
   445
abbreviation "total \<equiv> total_on UNIV"
nipkow@29859
   446
haftmann@46752
   447
lemma total_on_empty [simp]: "total_on {} r"
haftmann@46752
   448
  by (simp add: total_on_def)
haftmann@46692
   449
haftmann@46692
   450
wenzelm@60758
   451
subsubsection \<open>Single valued relations\<close>
haftmann@46692
   452
haftmann@46752
   453
definition single_valued :: "('a \<times> 'b) set \<Rightarrow> bool"
haftmann@46752
   454
where
haftmann@46752
   455
  "single_valued r \<longleftrightarrow> (\<forall>x y. (x, y) \<in> r \<longrightarrow> (\<forall>z. (x, z) \<in> r \<longrightarrow> y = z))"
haftmann@46692
   456
haftmann@46694
   457
abbreviation single_valuedP :: "('a \<Rightarrow> 'b \<Rightarrow> bool) \<Rightarrow> bool" where
haftmann@46694
   458
  "single_valuedP r \<equiv> single_valued {(x, y). r x y}"
haftmann@46694
   459
haftmann@46752
   460
lemma single_valuedI:
haftmann@46752
   461
  "ALL x y. (x,y):r --> (ALL z. (x,z):r --> y=z) ==> single_valued r"
haftmann@46752
   462
  by (unfold single_valued_def)
haftmann@46752
   463
haftmann@46752
   464
lemma single_valuedD:
haftmann@46752
   465
  "single_valued r ==> (x, y) : r ==> (x, z) : r ==> y = z"
haftmann@46752
   466
  by (simp add: single_valued_def)
haftmann@46752
   467
nipkow@57111
   468
lemma single_valued_empty[simp]: "single_valued {}"
nipkow@52392
   469
by(simp add: single_valued_def)
nipkow@52392
   470
haftmann@46692
   471
lemma single_valued_subset:
haftmann@46692
   472
  "r \<subseteq> s ==> single_valued s ==> single_valued r"
haftmann@46752
   473
  by (unfold single_valued_def) blast
oheimb@11136
   474
berghofe@12905
   475
wenzelm@60758
   476
subsection \<open>Relation operations\<close>
haftmann@46694
   477
wenzelm@60758
   478
subsubsection \<open>The identity relation\<close>
berghofe@12905
   479
haftmann@46752
   480
definition Id :: "'a rel"
haftmann@46752
   481
where
bulwahn@48253
   482
  [code del]: "Id = {p. \<exists>x. p = (x, x)}"
haftmann@46692
   483
berghofe@12905
   484
lemma IdI [intro]: "(a, a) : Id"
haftmann@46752
   485
  by (simp add: Id_def)
berghofe@12905
   486
berghofe@12905
   487
lemma IdE [elim!]: "p : Id ==> (!!x. p = (x, x) ==> P) ==> P"
haftmann@46752
   488
  by (unfold Id_def) (iprover elim: CollectE)
berghofe@12905
   489
berghofe@12905
   490
lemma pair_in_Id_conv [iff]: "((a, b) : Id) = (a = b)"
haftmann@46752
   491
  by (unfold Id_def) blast
berghofe@12905
   492
nipkow@30198
   493
lemma refl_Id: "refl Id"
haftmann@46752
   494
  by (simp add: refl_on_def)
berghofe@12905
   495
berghofe@12905
   496
lemma antisym_Id: "antisym Id"
wenzelm@61799
   497
  \<comment> \<open>A strange result, since \<open>Id\<close> is also symmetric.\<close>
haftmann@46752
   498
  by (simp add: antisym_def)
berghofe@12905
   499
huffman@19228
   500
lemma sym_Id: "sym Id"
haftmann@46752
   501
  by (simp add: sym_def)
huffman@19228
   502
berghofe@12905
   503
lemma trans_Id: "trans Id"
haftmann@46752
   504
  by (simp add: trans_def)
berghofe@12905
   505
haftmann@46692
   506
lemma single_valued_Id [simp]: "single_valued Id"
haftmann@46692
   507
  by (unfold single_valued_def) blast
haftmann@46692
   508
haftmann@46692
   509
lemma irrefl_diff_Id [simp]: "irrefl (r - Id)"
haftmann@46692
   510
  by (simp add:irrefl_def)
haftmann@46692
   511
haftmann@46692
   512
lemma trans_diff_Id: "trans r \<Longrightarrow> antisym r \<Longrightarrow> trans (r - Id)"
haftmann@46692
   513
  unfolding antisym_def trans_def by blast
haftmann@46692
   514
haftmann@46692
   515
lemma total_on_diff_Id [simp]: "total_on A (r - Id) = total_on A r"
haftmann@46692
   516
  by (simp add: total_on_def)
haftmann@46692
   517
paulson@62087
   518
lemma Id_fstsnd_eq: "Id = {x. fst x = snd x}"
paulson@62087
   519
  by force
berghofe@12905
   520
wenzelm@60758
   521
subsubsection \<open>Diagonal: identity over a set\<close>
berghofe@12905
   522
haftmann@46752
   523
definition Id_on  :: "'a set \<Rightarrow> 'a rel"
haftmann@46752
   524
where
haftmann@46752
   525
  "Id_on A = (\<Union>x\<in>A. {(x, x)})"
haftmann@46692
   526
nipkow@30198
   527
lemma Id_on_empty [simp]: "Id_on {} = {}"
haftmann@46752
   528
  by (simp add: Id_on_def) 
paulson@13812
   529
nipkow@30198
   530
lemma Id_on_eqI: "a = b ==> a : A ==> (a, b) : Id_on A"
haftmann@46752
   531
  by (simp add: Id_on_def)
berghofe@12905
   532
blanchet@54147
   533
lemma Id_onI [intro!]: "a : A ==> (a, a) : Id_on A"
haftmann@46752
   534
  by (rule Id_on_eqI) (rule refl)
berghofe@12905
   535
nipkow@30198
   536
lemma Id_onE [elim!]:
nipkow@30198
   537
  "c : Id_on A ==> (!!x. x : A ==> c = (x, x) ==> P) ==> P"
wenzelm@61799
   538
  \<comment> \<open>The general elimination rule.\<close>
haftmann@46752
   539
  by (unfold Id_on_def) (iprover elim!: UN_E singletonE)
berghofe@12905
   540
nipkow@30198
   541
lemma Id_on_iff: "((x, y) : Id_on A) = (x = y & x : A)"
haftmann@46752
   542
  by blast
berghofe@12905
   543
haftmann@45967
   544
lemma Id_on_def' [nitpick_unfold]:
haftmann@44278
   545
  "Id_on {x. A x} = Collect (\<lambda>(x, y). x = y \<and> A x)"
haftmann@46752
   546
  by auto
bulwahn@40923
   547
nipkow@30198
   548
lemma Id_on_subset_Times: "Id_on A \<subseteq> A \<times> A"
haftmann@46752
   549
  by blast
berghofe@12905
   550
haftmann@46692
   551
lemma refl_on_Id_on: "refl_on A (Id_on A)"
haftmann@46752
   552
  by (rule refl_onI [OF Id_on_subset_Times Id_onI])
haftmann@46692
   553
haftmann@46692
   554
lemma antisym_Id_on [simp]: "antisym (Id_on A)"
haftmann@46752
   555
  by (unfold antisym_def) blast
haftmann@46692
   556
haftmann@46692
   557
lemma sym_Id_on [simp]: "sym (Id_on A)"
haftmann@46752
   558
  by (rule symI) clarify
haftmann@46692
   559
haftmann@46692
   560
lemma trans_Id_on [simp]: "trans (Id_on A)"
haftmann@46752
   561
  by (fast intro: transI elim: transD)
haftmann@46692
   562
haftmann@46692
   563
lemma single_valued_Id_on [simp]: "single_valued (Id_on A)"
haftmann@46692
   564
  by (unfold single_valued_def) blast
haftmann@46692
   565
berghofe@12905
   566
wenzelm@60758
   567
subsubsection \<open>Composition\<close>
berghofe@12905
   568
griff@47433
   569
inductive_set relcomp  :: "('a \<times> 'b) set \<Rightarrow> ('b \<times> 'c) set \<Rightarrow> ('a \<times> 'c) set" (infixr "O" 75)
haftmann@46752
   570
  for r :: "('a \<times> 'b) set" and s :: "('b \<times> 'c) set"
haftmann@46694
   571
where
griff@47433
   572
  relcompI [intro]: "(a, b) \<in> r \<Longrightarrow> (b, c) \<in> s \<Longrightarrow> (a, c) \<in> r O s"
haftmann@46692
   573
griff@47434
   574
notation relcompp (infixr "OO" 75)
berghofe@12905
   575
griff@47434
   576
lemmas relcomppI = relcompp.intros
berghofe@12905
   577
wenzelm@60758
   578
text \<open>
haftmann@46752
   579
  For historic reasons, the elimination rules are not wholly corresponding.
haftmann@46752
   580
  Feel free to consolidate this.
wenzelm@60758
   581
\<close>
haftmann@46694
   582
griff@47433
   583
inductive_cases relcompEpair: "(a, c) \<in> r O s"
griff@47434
   584
inductive_cases relcomppE [elim!]: "(r OO s) a c"
haftmann@46694
   585
griff@47433
   586
lemma relcompE [elim!]: "xz \<in> r O s \<Longrightarrow>
haftmann@46752
   587
  (\<And>x y z. xz = (x, z) \<Longrightarrow> (x, y) \<in> r \<Longrightarrow> (y, z) \<in> s  \<Longrightarrow> P) \<Longrightarrow> P"
griff@47433
   588
  by (cases xz) (simp, erule relcompEpair, iprover)
haftmann@46752
   589
haftmann@46752
   590
lemma R_O_Id [simp]:
haftmann@46752
   591
  "R O Id = R"
haftmann@46752
   592
  by fast
haftmann@46694
   593
haftmann@46752
   594
lemma Id_O_R [simp]:
haftmann@46752
   595
  "Id O R = R"
haftmann@46752
   596
  by fast
haftmann@46752
   597
griff@47433
   598
lemma relcomp_empty1 [simp]:
haftmann@46752
   599
  "{} O R = {}"
haftmann@46752
   600
  by blast
berghofe@12905
   601
griff@47434
   602
lemma relcompp_bot1 [simp]:
noschinl@46883
   603
  "\<bottom> OO R = \<bottom>"
griff@47433
   604
  by (fact relcomp_empty1 [to_pred])
berghofe@12905
   605
griff@47433
   606
lemma relcomp_empty2 [simp]:
haftmann@46752
   607
  "R O {} = {}"
haftmann@46752
   608
  by blast
berghofe@12905
   609
griff@47434
   610
lemma relcompp_bot2 [simp]:
noschinl@46883
   611
  "R OO \<bottom> = \<bottom>"
griff@47433
   612
  by (fact relcomp_empty2 [to_pred])
krauss@23185
   613
haftmann@46752
   614
lemma O_assoc:
haftmann@46752
   615
  "(R O S) O T = R O (S O T)"
haftmann@46752
   616
  by blast
haftmann@46752
   617
griff@47434
   618
lemma relcompp_assoc:
haftmann@46752
   619
  "(r OO s) OO t = r OO (s OO t)"
haftmann@46752
   620
  by (fact O_assoc [to_pred])
krauss@23185
   621
haftmann@46752
   622
lemma trans_O_subset:
haftmann@46752
   623
  "trans r \<Longrightarrow> r O r \<subseteq> r"
haftmann@46752
   624
  by (unfold trans_def) blast
haftmann@46752
   625
griff@47434
   626
lemma transp_relcompp_less_eq:
haftmann@46752
   627
  "transp r \<Longrightarrow> r OO r \<le> r "
haftmann@46752
   628
  by (fact trans_O_subset [to_pred])
berghofe@12905
   629
griff@47433
   630
lemma relcomp_mono:
haftmann@46752
   631
  "r' \<subseteq> r \<Longrightarrow> s' \<subseteq> s \<Longrightarrow> r' O s' \<subseteq> r O s"
haftmann@46752
   632
  by blast
berghofe@12905
   633
griff@47434
   634
lemma relcompp_mono:
haftmann@46752
   635
  "r' \<le> r \<Longrightarrow> s' \<le> s \<Longrightarrow> r' OO s' \<le> r OO s "
griff@47433
   636
  by (fact relcomp_mono [to_pred])
berghofe@12905
   637
griff@47433
   638
lemma relcomp_subset_Sigma:
haftmann@46752
   639
  "r \<subseteq> A \<times> B \<Longrightarrow> s \<subseteq> B \<times> C \<Longrightarrow> r O s \<subseteq> A \<times> C"
haftmann@46752
   640
  by blast
haftmann@46752
   641
griff@47433
   642
lemma relcomp_distrib [simp]:
haftmann@46752
   643
  "R O (S \<union> T) = (R O S) \<union> (R O T)" 
haftmann@46752
   644
  by auto
berghofe@12905
   645
griff@47434
   646
lemma relcompp_distrib [simp]:
haftmann@46752
   647
  "R OO (S \<squnion> T) = R OO S \<squnion> R OO T"
griff@47433
   648
  by (fact relcomp_distrib [to_pred])
haftmann@46752
   649
griff@47433
   650
lemma relcomp_distrib2 [simp]:
haftmann@46752
   651
  "(S \<union> T) O R = (S O R) \<union> (T O R)"
haftmann@46752
   652
  by auto
krauss@28008
   653
griff@47434
   654
lemma relcompp_distrib2 [simp]:
haftmann@46752
   655
  "(S \<squnion> T) OO R = S OO R \<squnion> T OO R"
griff@47433
   656
  by (fact relcomp_distrib2 [to_pred])
haftmann@46752
   657
griff@47433
   658
lemma relcomp_UNION_distrib:
haftmann@46752
   659
  "s O UNION I r = (\<Union>i\<in>I. s O r i) "
haftmann@46752
   660
  by auto
krauss@28008
   661
griff@47433
   662
(* FIXME thm relcomp_UNION_distrib [to_pred] *)
krauss@36772
   663
griff@47433
   664
lemma relcomp_UNION_distrib2:
haftmann@46752
   665
  "UNION I r O s = (\<Union>i\<in>I. r i O s) "
haftmann@46752
   666
  by auto
haftmann@46752
   667
griff@47433
   668
(* FIXME thm relcomp_UNION_distrib2 [to_pred] *)
krauss@36772
   669
griff@47433
   670
lemma single_valued_relcomp:
haftmann@46752
   671
  "single_valued r \<Longrightarrow> single_valued s \<Longrightarrow> single_valued (r O s)"
haftmann@46752
   672
  by (unfold single_valued_def) blast
haftmann@46752
   673
griff@47433
   674
lemma relcomp_unfold:
haftmann@46752
   675
  "r O s = {(x, z). \<exists>y. (x, y) \<in> r \<and> (y, z) \<in> s}"
haftmann@46752
   676
  by (auto simp add: set_eq_iff)
berghofe@12905
   677
haftmann@58195
   678
lemma relcompp_apply: "(R OO S) a c \<longleftrightarrow> (\<exists>b. R a b \<and> S b c)"
haftmann@58195
   679
  unfolding relcomp_unfold [to_pred] ..
haftmann@58195
   680
blanchet@55083
   681
lemma eq_OO: "op= OO R = R"
blanchet@55083
   682
by blast
blanchet@55083
   683
Andreas@61630
   684
lemma OO_eq: "R OO op = = R"
Andreas@61630
   685
by blast
haftmann@46664
   686
wenzelm@60758
   687
subsubsection \<open>Converse\<close>
wenzelm@12913
   688
wenzelm@61955
   689
inductive_set converse :: "('a \<times> 'b) set \<Rightarrow> ('b \<times> 'a) set"  ("(_\<inverse>)" [1000] 999)
haftmann@46752
   690
  for r :: "('a \<times> 'b) set"
haftmann@46752
   691
where
wenzelm@61955
   692
  "(a, b) \<in> r \<Longrightarrow> (b, a) \<in> r\<inverse>"
haftmann@46692
   693
haftmann@46752
   694
notation
wenzelm@61955
   695
  conversep  ("(_\<inverse>\<inverse>)" [1000] 1000)
haftmann@46694
   696
wenzelm@61955
   697
notation (ASCII)
wenzelm@61955
   698
  converse  ("(_^-1)" [1000] 999) and
wenzelm@61955
   699
  conversep ("(_^--1)" [1000] 1000)
haftmann@46694
   700
haftmann@46752
   701
lemma converseI [sym]:
haftmann@46752
   702
  "(a, b) \<in> r \<Longrightarrow> (b, a) \<in> r\<inverse>"
haftmann@46752
   703
  by (fact converse.intros)
haftmann@46752
   704
haftmann@46752
   705
lemma conversepI (* CANDIDATE [sym] *):
haftmann@46752
   706
  "r a b \<Longrightarrow> r\<inverse>\<inverse> b a"
haftmann@46752
   707
  by (fact conversep.intros)
haftmann@46752
   708
haftmann@46752
   709
lemma converseD [sym]:
haftmann@46752
   710
  "(a, b) \<in> r\<inverse> \<Longrightarrow> (b, a) \<in> r"
haftmann@46752
   711
  by (erule converse.cases) iprover
haftmann@46752
   712
haftmann@46752
   713
lemma conversepD (* CANDIDATE [sym] *):
haftmann@46752
   714
  "r\<inverse>\<inverse> b a \<Longrightarrow> r a b"
haftmann@46752
   715
  by (fact converseD [to_pred])
haftmann@46752
   716
haftmann@46752
   717
lemma converseE [elim!]:
wenzelm@61799
   718
  \<comment> \<open>More general than \<open>converseD\<close>, as it ``splits'' the member of the relation.\<close>
haftmann@46752
   719
  "yx \<in> r\<inverse> \<Longrightarrow> (\<And>x y. yx = (y, x) \<Longrightarrow> (x, y) \<in> r \<Longrightarrow> P) \<Longrightarrow> P"
haftmann@46752
   720
  by (cases yx) (simp, erule converse.cases, iprover)
haftmann@46694
   721
noschinl@46882
   722
lemmas conversepE [elim!] = conversep.cases
haftmann@46752
   723
haftmann@46752
   724
lemma converse_iff [iff]:
haftmann@46752
   725
  "(a, b) \<in> r\<inverse> \<longleftrightarrow> (b, a) \<in> r"
haftmann@46752
   726
  by (auto intro: converseI)
haftmann@46752
   727
haftmann@46752
   728
lemma conversep_iff [iff]:
haftmann@46752
   729
  "r\<inverse>\<inverse> a b = r b a"
haftmann@46752
   730
  by (fact converse_iff [to_pred])
haftmann@46694
   731
haftmann@46752
   732
lemma converse_converse [simp]:
haftmann@46752
   733
  "(r\<inverse>)\<inverse> = r"
haftmann@46752
   734
  by (simp add: set_eq_iff)
haftmann@46694
   735
haftmann@46752
   736
lemma conversep_conversep [simp]:
haftmann@46752
   737
  "(r\<inverse>\<inverse>)\<inverse>\<inverse> = r"
haftmann@46752
   738
  by (fact converse_converse [to_pred])
haftmann@46752
   739
nipkow@53680
   740
lemma converse_empty[simp]: "{}\<inverse> = {}"
nipkow@53680
   741
by auto
nipkow@53680
   742
nipkow@53680
   743
lemma converse_UNIV[simp]: "UNIV\<inverse> = UNIV"
nipkow@53680
   744
by auto
nipkow@53680
   745
griff@47433
   746
lemma converse_relcomp: "(r O s)^-1 = s^-1 O r^-1"
haftmann@46752
   747
  by blast
haftmann@46694
   748
griff@47434
   749
lemma converse_relcompp: "(r OO s)^--1 = s^--1 OO r^--1"
griff@47434
   750
  by (iprover intro: order_antisym conversepI relcomppI
griff@47434
   751
    elim: relcomppE dest: conversepD)
haftmann@46694
   752
haftmann@46752
   753
lemma converse_Int: "(r \<inter> s)^-1 = r^-1 \<inter> s^-1"
haftmann@46752
   754
  by blast
haftmann@46752
   755
haftmann@46694
   756
lemma converse_meet: "(r \<sqinter> s)^--1 = r^--1 \<sqinter> s^--1"
haftmann@46694
   757
  by (simp add: inf_fun_def) (iprover intro: conversepI ext dest: conversepD)
haftmann@46694
   758
haftmann@46752
   759
lemma converse_Un: "(r \<union> s)^-1 = r^-1 \<union> s^-1"
haftmann@46752
   760
  by blast
haftmann@46752
   761
haftmann@46694
   762
lemma converse_join: "(r \<squnion> s)^--1 = r^--1 \<squnion> s^--1"
haftmann@46694
   763
  by (simp add: sup_fun_def) (iprover intro: conversepI ext dest: conversepD)
haftmann@46694
   764
huffman@19228
   765
lemma converse_INTER: "(INTER S r)^-1 = (INT x:S. (r x)^-1)"
haftmann@46752
   766
  by fast
huffman@19228
   767
huffman@19228
   768
lemma converse_UNION: "(UNION S r)^-1 = (UN x:S. (r x)^-1)"
haftmann@46752
   769
  by blast
huffman@19228
   770
traytel@52749
   771
lemma converse_mono[simp]: "r^-1 \<subseteq> s ^-1 \<longleftrightarrow> r \<subseteq> s"
traytel@52749
   772
  by auto
traytel@52749
   773
traytel@52749
   774
lemma conversep_mono[simp]: "r^--1 \<le> s ^--1 \<longleftrightarrow> r \<le> s"
traytel@52749
   775
  by (fact converse_mono[to_pred])
traytel@52749
   776
traytel@52749
   777
lemma converse_inject[simp]: "r^-1 = s ^-1 \<longleftrightarrow> r = s"
traytel@52730
   778
  by auto
traytel@52730
   779
traytel@52749
   780
lemma conversep_inject[simp]: "r^--1 = s ^--1 \<longleftrightarrow> r = s"
traytel@52749
   781
  by (fact converse_inject[to_pred])
traytel@52749
   782
traytel@52749
   783
lemma converse_subset_swap: "r \<subseteq> s ^-1 = (r ^-1 \<subseteq> s)"
traytel@52749
   784
  by auto
traytel@52749
   785
traytel@52749
   786
lemma conversep_le_swap: "r \<le> s ^--1 = (r ^--1 \<le> s)"
traytel@52749
   787
  by (fact converse_subset_swap[to_pred])
traytel@52730
   788
berghofe@12905
   789
lemma converse_Id [simp]: "Id^-1 = Id"
haftmann@46752
   790
  by blast
berghofe@12905
   791
nipkow@30198
   792
lemma converse_Id_on [simp]: "(Id_on A)^-1 = Id_on A"
haftmann@46752
   793
  by blast
berghofe@12905
   794
nipkow@30198
   795
lemma refl_on_converse [simp]: "refl_on A (converse r) = refl_on A r"
haftmann@46752
   796
  by (unfold refl_on_def) auto
berghofe@12905
   797
huffman@19228
   798
lemma sym_converse [simp]: "sym (converse r) = sym r"
haftmann@46752
   799
  by (unfold sym_def) blast
huffman@19228
   800
huffman@19228
   801
lemma antisym_converse [simp]: "antisym (converse r) = antisym r"
haftmann@46752
   802
  by (unfold antisym_def) blast
berghofe@12905
   803
huffman@19228
   804
lemma trans_converse [simp]: "trans (converse r) = trans r"
haftmann@46752
   805
  by (unfold trans_def) blast
berghofe@12905
   806
huffman@19228
   807
lemma sym_conv_converse_eq: "sym r = (r^-1 = r)"
haftmann@46752
   808
  by (unfold sym_def) fast
huffman@19228
   809
huffman@19228
   810
lemma sym_Un_converse: "sym (r \<union> r^-1)"
haftmann@46752
   811
  by (unfold sym_def) blast
huffman@19228
   812
huffman@19228
   813
lemma sym_Int_converse: "sym (r \<inter> r^-1)"
haftmann@46752
   814
  by (unfold sym_def) blast
huffman@19228
   815
haftmann@46752
   816
lemma total_on_converse [simp]: "total_on A (r^-1) = total_on A r"
haftmann@46752
   817
  by (auto simp: total_on_def)
nipkow@29859
   818
traytel@52749
   819
lemma finite_converse [iff]: "finite (r^-1) = finite r"  
traytel@54611
   820
  unfolding converse_def conversep_iff using [[simproc add: finite_Collect]]
traytel@54611
   821
  by (auto elim: finite_imageD simp: inj_on_def)
wenzelm@12913
   822
haftmann@46752
   823
lemma conversep_noteq [simp]: "(op \<noteq>)^--1 = op \<noteq>"
haftmann@46752
   824
  by (auto simp add: fun_eq_iff)
haftmann@46752
   825
haftmann@46752
   826
lemma conversep_eq [simp]: "(op =)^--1 = op ="
haftmann@46752
   827
  by (auto simp add: fun_eq_iff)
haftmann@46752
   828
nipkow@53680
   829
lemma converse_unfold [code]:
haftmann@46752
   830
  "r\<inverse> = {(y, x). (x, y) \<in> r}"
haftmann@46752
   831
  by (simp add: set_eq_iff)
haftmann@46752
   832
haftmann@46692
   833
wenzelm@60758
   834
subsubsection \<open>Domain, range and field\<close>
haftmann@46692
   835
haftmann@46767
   836
inductive_set Domain :: "('a \<times> 'b) set \<Rightarrow> 'a set"
haftmann@46767
   837
  for r :: "('a \<times> 'b) set"
haftmann@46752
   838
where
haftmann@46767
   839
  DomainI [intro]: "(a, b) \<in> r \<Longrightarrow> a \<in> Domain r"
haftmann@46767
   840
haftmann@46767
   841
abbreviation (input) "DomainP \<equiv> Domainp"
haftmann@46767
   842
haftmann@46767
   843
lemmas DomainPI = Domainp.DomainI
haftmann@46767
   844
haftmann@46767
   845
inductive_cases DomainE [elim!]: "a \<in> Domain r"
haftmann@46767
   846
inductive_cases DomainpE [elim!]: "Domainp r a"
haftmann@46692
   847
haftmann@46767
   848
inductive_set Range :: "('a \<times> 'b) set \<Rightarrow> 'b set"
haftmann@46767
   849
  for r :: "('a \<times> 'b) set"
haftmann@46752
   850
where
haftmann@46767
   851
  RangeI [intro]: "(a, b) \<in> r \<Longrightarrow> b \<in> Range r"
haftmann@46767
   852
haftmann@46767
   853
abbreviation (input) "RangeP \<equiv> Rangep"
haftmann@46767
   854
haftmann@46767
   855
lemmas RangePI = Rangep.RangeI
haftmann@46767
   856
haftmann@46767
   857
inductive_cases RangeE [elim!]: "b \<in> Range r"
haftmann@46767
   858
inductive_cases RangepE [elim!]: "Rangep r b"
haftmann@46692
   859
haftmann@46752
   860
definition Field :: "'a rel \<Rightarrow> 'a set"
haftmann@46752
   861
where
haftmann@46692
   862
  "Field r = Domain r \<union> Range r"
berghofe@12905
   863
haftmann@46694
   864
lemma Domain_fst [code]:
haftmann@46694
   865
  "Domain r = fst ` r"
haftmann@46767
   866
  by force
haftmann@46767
   867
haftmann@46767
   868
lemma Range_snd [code]:
haftmann@46767
   869
  "Range r = snd ` r"
haftmann@46767
   870
  by force
haftmann@46767
   871
haftmann@46767
   872
lemma fst_eq_Domain: "fst ` R = Domain R"
haftmann@46767
   873
  by force
haftmann@46767
   874
haftmann@46767
   875
lemma snd_eq_Range: "snd ` R = Range R"
haftmann@46767
   876
  by force
haftmann@46694
   877
paulson@62087
   878
lemma range_fst [simp]: "range fst = UNIV"
paulson@62087
   879
  by (auto simp: fst_eq_Domain)
paulson@62087
   880
paulson@62087
   881
lemma range_snd [simp]: "range snd = UNIV"
paulson@62087
   882
  by (auto simp: snd_eq_Range)
paulson@62087
   883
haftmann@46694
   884
lemma Domain_empty [simp]: "Domain {} = {}"
haftmann@46767
   885
  by auto
haftmann@46767
   886
haftmann@46767
   887
lemma Range_empty [simp]: "Range {} = {}"
haftmann@46767
   888
  by auto
haftmann@46767
   889
haftmann@46767
   890
lemma Field_empty [simp]: "Field {} = {}"
haftmann@46767
   891
  by (simp add: Field_def)
haftmann@46694
   892
haftmann@46694
   893
lemma Domain_empty_iff: "Domain r = {} \<longleftrightarrow> r = {}"
haftmann@46694
   894
  by auto
haftmann@46694
   895
haftmann@46767
   896
lemma Range_empty_iff: "Range r = {} \<longleftrightarrow> r = {}"
haftmann@46767
   897
  by auto
haftmann@46767
   898
noschinl@46882
   899
lemma Domain_insert [simp]: "Domain (insert (a, b) r) = insert a (Domain r)"
haftmann@46767
   900
  by blast
haftmann@46767
   901
noschinl@46882
   902
lemma Range_insert [simp]: "Range (insert (a, b) r) = insert b (Range r)"
haftmann@46767
   903
  by blast
haftmann@46767
   904
haftmann@46767
   905
lemma Field_insert [simp]: "Field (insert (a, b) r) = {a, b} \<union> Field r"
noschinl@46884
   906
  by (auto simp add: Field_def)
haftmann@46767
   907
haftmann@46767
   908
lemma Domain_iff: "a \<in> Domain r \<longleftrightarrow> (\<exists>y. (a, y) \<in> r)"
haftmann@46767
   909
  by blast
haftmann@46767
   910
haftmann@46767
   911
lemma Range_iff: "a \<in> Range r \<longleftrightarrow> (\<exists>y. (y, a) \<in> r)"
haftmann@46694
   912
  by blast
haftmann@46694
   913
haftmann@46694
   914
lemma Domain_Id [simp]: "Domain Id = UNIV"
haftmann@46694
   915
  by blast
haftmann@46694
   916
haftmann@46767
   917
lemma Range_Id [simp]: "Range Id = UNIV"
haftmann@46767
   918
  by blast
haftmann@46767
   919
haftmann@46694
   920
lemma Domain_Id_on [simp]: "Domain (Id_on A) = A"
haftmann@46694
   921
  by blast
haftmann@46694
   922
haftmann@46767
   923
lemma Range_Id_on [simp]: "Range (Id_on A) = A"
haftmann@46767
   924
  by blast
haftmann@46767
   925
haftmann@46767
   926
lemma Domain_Un_eq: "Domain (A \<union> B) = Domain A \<union> Domain B"
haftmann@46694
   927
  by blast
haftmann@46694
   928
haftmann@46767
   929
lemma Range_Un_eq: "Range (A \<union> B) = Range A \<union> Range B"
haftmann@46767
   930
  by blast
haftmann@46767
   931
haftmann@46767
   932
lemma Field_Un [simp]: "Field (r \<union> s) = Field r \<union> Field s"
haftmann@46767
   933
  by (auto simp: Field_def)
haftmann@46767
   934
haftmann@46767
   935
lemma Domain_Int_subset: "Domain (A \<inter> B) \<subseteq> Domain A \<inter> Domain B"
haftmann@46694
   936
  by blast
haftmann@46694
   937
haftmann@46767
   938
lemma Range_Int_subset: "Range (A \<inter> B) \<subseteq> Range A \<inter> Range B"
haftmann@46767
   939
  by blast
haftmann@46767
   940
haftmann@46767
   941
lemma Domain_Diff_subset: "Domain A - Domain B \<subseteq> Domain (A - B)"
haftmann@46767
   942
  by blast
haftmann@46767
   943
haftmann@46767
   944
lemma Range_Diff_subset: "Range A - Range B \<subseteq> Range (A - B)"
haftmann@46694
   945
  by blast
haftmann@46694
   946
haftmann@46767
   947
lemma Domain_Union: "Domain (\<Union>S) = (\<Union>A\<in>S. Domain A)"
haftmann@46694
   948
  by blast
haftmann@46694
   949
haftmann@46767
   950
lemma Range_Union: "Range (\<Union>S) = (\<Union>A\<in>S. Range A)"
haftmann@46767
   951
  by blast
haftmann@46767
   952
haftmann@46767
   953
lemma Field_Union [simp]: "Field (\<Union>R) = \<Union>(Field ` R)"
haftmann@46767
   954
  by (auto simp: Field_def)
haftmann@46767
   955
haftmann@46752
   956
lemma Domain_converse [simp]: "Domain (r\<inverse>) = Range r"
haftmann@46752
   957
  by auto
haftmann@46694
   958
haftmann@46767
   959
lemma Range_converse [simp]: "Range (r\<inverse>) = Domain r"
haftmann@46694
   960
  by blast
haftmann@46694
   961
haftmann@46767
   962
lemma Field_converse [simp]: "Field (r\<inverse>) = Field r"
haftmann@46767
   963
  by (auto simp: Field_def)
haftmann@46767
   964
haftmann@61424
   965
lemma Domain_Collect_case_prod [simp]: "Domain {(x, y). P x y} = {x. EX y. P x y}"
haftmann@46767
   966
  by auto
haftmann@46767
   967
haftmann@61424
   968
lemma Range_Collect_case_prod [simp]: "Range {(x, y). P x y} = {y. EX x. P x y}"
haftmann@46767
   969
  by auto
haftmann@46767
   970
haftmann@46767
   971
lemma finite_Domain: "finite r \<Longrightarrow> finite (Domain r)"
noschinl@46884
   972
  by (induct set: finite) auto
haftmann@46767
   973
haftmann@46767
   974
lemma finite_Range: "finite r \<Longrightarrow> finite (Range r)"
noschinl@46884
   975
  by (induct set: finite) auto
haftmann@46767
   976
haftmann@46767
   977
lemma finite_Field: "finite r \<Longrightarrow> finite (Field r)"
haftmann@46767
   978
  by (simp add: Field_def finite_Domain finite_Range)
haftmann@46767
   979
haftmann@46767
   980
lemma Domain_mono: "r \<subseteq> s \<Longrightarrow> Domain r \<subseteq> Domain s"
haftmann@46767
   981
  by blast
haftmann@46767
   982
haftmann@46767
   983
lemma Range_mono: "r \<subseteq> s \<Longrightarrow> Range r \<subseteq> Range s"
haftmann@46767
   984
  by blast
haftmann@46767
   985
haftmann@46767
   986
lemma mono_Field: "r \<subseteq> s \<Longrightarrow> Field r \<subseteq> Field s"
haftmann@46767
   987
  by (auto simp: Field_def Domain_def Range_def)
haftmann@46767
   988
haftmann@46767
   989
lemma Domain_unfold:
haftmann@46767
   990
  "Domain r = {x. \<exists>y. (x, y) \<in> r}"
haftmann@46767
   991
  by blast
haftmann@46694
   992
berghofe@12905
   993
wenzelm@60758
   994
subsubsection \<open>Image of a set under a relation\<close>
berghofe@12905
   995
nipkow@50420
   996
definition Image :: "('a \<times> 'b) set \<Rightarrow> 'a set \<Rightarrow> 'b set" (infixr "``" 90)
haftmann@46752
   997
where
haftmann@46752
   998
  "r `` s = {y. \<exists>x\<in>s. (x, y) \<in> r}"
haftmann@46692
   999
wenzelm@12913
  1000
lemma Image_iff: "(b : r``A) = (EX x:A. (x, b) : r)"
haftmann@46752
  1001
  by (simp add: Image_def)
berghofe@12905
  1002
wenzelm@12913
  1003
lemma Image_singleton: "r``{a} = {b. (a, b) : r}"
haftmann@46752
  1004
  by (simp add: Image_def)
berghofe@12905
  1005
wenzelm@12913
  1006
lemma Image_singleton_iff [iff]: "(b : r``{a}) = ((a, b) : r)"
haftmann@46752
  1007
  by (rule Image_iff [THEN trans]) simp
berghofe@12905
  1008
blanchet@54147
  1009
lemma ImageI [intro]: "(a, b) : r ==> a : A ==> b : r``A"
haftmann@46752
  1010
  by (unfold Image_def) blast
berghofe@12905
  1011
berghofe@12905
  1012
lemma ImageE [elim!]:
haftmann@46752
  1013
  "b : r `` A ==> (!!x. (x, b) : r ==> x : A ==> P) ==> P"
haftmann@46752
  1014
  by (unfold Image_def) (iprover elim!: CollectE bexE)
berghofe@12905
  1015
berghofe@12905
  1016
lemma rev_ImageI: "a : A ==> (a, b) : r ==> b : r `` A"
wenzelm@61799
  1017
  \<comment> \<open>This version's more effective when we already have the required \<open>a\<close>\<close>
haftmann@46752
  1018
  by blast
berghofe@12905
  1019
berghofe@12905
  1020
lemma Image_empty [simp]: "R``{} = {}"
haftmann@46752
  1021
  by blast
berghofe@12905
  1022
berghofe@12905
  1023
lemma Image_Id [simp]: "Id `` A = A"
haftmann@46752
  1024
  by blast
berghofe@12905
  1025
nipkow@30198
  1026
lemma Image_Id_on [simp]: "Id_on A `` B = A \<inter> B"
haftmann@46752
  1027
  by blast
paulson@13830
  1028
paulson@13830
  1029
lemma Image_Int_subset: "R `` (A \<inter> B) \<subseteq> R `` A \<inter> R `` B"
haftmann@46752
  1030
  by blast
berghofe@12905
  1031
paulson@13830
  1032
lemma Image_Int_eq:
haftmann@46767
  1033
  "single_valued (converse R) ==> R `` (A \<inter> B) = R `` A \<inter> R `` B"
haftmann@46767
  1034
  by (simp add: single_valued_def, blast) 
berghofe@12905
  1035
paulson@13830
  1036
lemma Image_Un: "R `` (A \<union> B) = R `` A \<union> R `` B"
haftmann@46752
  1037
  by blast
berghofe@12905
  1038
paulson@13812
  1039
lemma Un_Image: "(R \<union> S) `` A = R `` A \<union> S `` A"
haftmann@46752
  1040
  by blast
paulson@13812
  1041
wenzelm@12913
  1042
lemma Image_subset: "r \<subseteq> A \<times> B ==> r``C \<subseteq> B"
haftmann@46752
  1043
  by (iprover intro!: subsetI elim!: ImageE dest!: subsetD SigmaD2)
berghofe@12905
  1044
paulson@13830
  1045
lemma Image_eq_UN: "r``B = (\<Union>y\<in> B. r``{y})"
wenzelm@61799
  1046
  \<comment> \<open>NOT suitable for rewriting\<close>
haftmann@46752
  1047
  by blast
berghofe@12905
  1048
wenzelm@12913
  1049
lemma Image_mono: "r' \<subseteq> r ==> A' \<subseteq> A ==> (r' `` A') \<subseteq> (r `` A)"
haftmann@46752
  1050
  by blast
berghofe@12905
  1051
paulson@13830
  1052
lemma Image_UN: "(r `` (UNION A B)) = (\<Union>x\<in>A. r `` (B x))"
haftmann@46752
  1053
  by blast
paulson@13830
  1054
hoelzl@54410
  1055
lemma UN_Image: "(\<Union>i\<in>I. X i) `` S = (\<Union>i\<in>I. X i `` S)"
hoelzl@54410
  1056
  by auto
hoelzl@54410
  1057
paulson@13830
  1058
lemma Image_INT_subset: "(r `` INTER A B) \<subseteq> (\<Inter>x\<in>A. r `` (B x))"
haftmann@46752
  1059
  by blast
berghofe@12905
  1060
wenzelm@60758
  1061
text\<open>Converse inclusion requires some assumptions\<close>
paulson@13830
  1062
lemma Image_INT_eq:
haftmann@62343
  1063
  "single_valued (r\<inverse>) \<Longrightarrow> A \<noteq> {} \<Longrightarrow> r `` INTER A B = (\<Inter>x\<in>A. r `` B x)"
paulson@13830
  1064
apply (rule equalityI)
paulson@13830
  1065
 apply (rule Image_INT_subset) 
haftmann@62343
  1066
apply (auto simp add: single_valued_def)
haftmann@62343
  1067
apply blast
paulson@13830
  1068
done
berghofe@12905
  1069
wenzelm@12913
  1070
lemma Image_subset_eq: "(r``A \<subseteq> B) = (A \<subseteq> - ((r^-1) `` (-B)))"
haftmann@46752
  1071
  by blast
berghofe@12905
  1072
haftmann@61424
  1073
lemma Image_Collect_case_prod [simp]: "{(x, y). P x y} `` A = {y. EX x:A. P x y}"
haftmann@46752
  1074
  by auto
berghofe@12905
  1075
hoelzl@54410
  1076
lemma Sigma_Image: "(SIGMA x:A. B x) `` X = (\<Union>x\<in>X \<inter> A. B x)"
hoelzl@54410
  1077
  by auto
hoelzl@54410
  1078
hoelzl@54410
  1079
lemma relcomp_Image: "(X O Y) `` Z = Y `` (X `` Z)"
hoelzl@54410
  1080
  by auto
berghofe@12905
  1081
wenzelm@60758
  1082
subsubsection \<open>Inverse image\<close>
berghofe@12905
  1083
haftmann@46752
  1084
definition inv_image :: "'b rel \<Rightarrow> ('a \<Rightarrow> 'b) \<Rightarrow> 'a rel"
haftmann@46752
  1085
where
haftmann@46752
  1086
  "inv_image r f = {(x, y). (f x, f y) \<in> r}"
haftmann@46692
  1087
haftmann@46752
  1088
definition inv_imagep :: "('b \<Rightarrow> 'b \<Rightarrow> bool) \<Rightarrow> ('a \<Rightarrow> 'b) \<Rightarrow> 'a \<Rightarrow> 'a \<Rightarrow> bool"
haftmann@46752
  1089
where
haftmann@46694
  1090
  "inv_imagep r f = (\<lambda>x y. r (f x) (f y))"
haftmann@46694
  1091
haftmann@46694
  1092
lemma [pred_set_conv]: "inv_imagep (\<lambda>x y. (x, y) \<in> r) f = (\<lambda>x y. (x, y) \<in> inv_image r f)"
haftmann@46694
  1093
  by (simp add: inv_image_def inv_imagep_def)
haftmann@46694
  1094
huffman@19228
  1095
lemma sym_inv_image: "sym r ==> sym (inv_image r f)"
haftmann@46752
  1096
  by (unfold sym_def inv_image_def) blast
huffman@19228
  1097
wenzelm@12913
  1098
lemma trans_inv_image: "trans r ==> trans (inv_image r f)"
berghofe@12905
  1099
  apply (unfold trans_def inv_image_def)
berghofe@12905
  1100
  apply (simp (no_asm))
berghofe@12905
  1101
  apply blast
berghofe@12905
  1102
  done
berghofe@12905
  1103
krauss@32463
  1104
lemma in_inv_image[simp]: "((x,y) : inv_image r f) = ((f x, f y) : r)"
krauss@32463
  1105
  by (auto simp:inv_image_def)
krauss@32463
  1106
krauss@33218
  1107
lemma converse_inv_image[simp]: "(inv_image R f)^-1 = inv_image (R^-1) f"
haftmann@46752
  1108
  unfolding inv_image_def converse_unfold by auto
krauss@33218
  1109
haftmann@46664
  1110
lemma in_inv_imagep [simp]: "inv_imagep r f x y = r (f x) (f y)"
haftmann@46664
  1111
  by (simp add: inv_imagep_def)
haftmann@46664
  1112
haftmann@46664
  1113
wenzelm@60758
  1114
subsubsection \<open>Powerset\<close>
haftmann@46664
  1115
haftmann@46752
  1116
definition Powp :: "('a \<Rightarrow> bool) \<Rightarrow> 'a set \<Rightarrow> bool"
haftmann@46752
  1117
where
haftmann@46664
  1118
  "Powp A = (\<lambda>B. \<forall>x \<in> B. A x)"
haftmann@46664
  1119
haftmann@46664
  1120
lemma Powp_Pow_eq [pred_set_conv]: "Powp (\<lambda>x. x \<in> A) = (\<lambda>x. x \<in> Pow A)"
haftmann@46664
  1121
  by (auto simp add: Powp_def fun_eq_iff)
haftmann@46664
  1122
haftmann@46664
  1123
lemmas Powp_mono [mono] = Pow_mono [to_pred]
haftmann@46664
  1124
wenzelm@60758
  1125
subsubsection \<open>Expressing relation operations via @{const Finite_Set.fold}\<close>
kuncar@48620
  1126
kuncar@48620
  1127
lemma Id_on_fold:
kuncar@48620
  1128
  assumes "finite A"
kuncar@48620
  1129
  shows "Id_on A = Finite_Set.fold (\<lambda>x. Set.insert (Pair x x)) {} A"
kuncar@48620
  1130
proof -
wenzelm@61169
  1131
  interpret comp_fun_commute "\<lambda>x. Set.insert (Pair x x)" by standard auto
kuncar@48620
  1132
  show ?thesis using assms unfolding Id_on_def by (induct A) simp_all
kuncar@48620
  1133
qed
kuncar@48620
  1134
kuncar@48620
  1135
lemma comp_fun_commute_Image_fold:
kuncar@48620
  1136
  "comp_fun_commute (\<lambda>(x,y) A. if x \<in> S then Set.insert y A else A)"
kuncar@48620
  1137
proof -
kuncar@48620
  1138
  interpret comp_fun_idem Set.insert
kuncar@48620
  1139
      by (fact comp_fun_idem_insert)
kuncar@48620
  1140
  show ?thesis 
wenzelm@61169
  1141
  by standard (auto simp add: fun_eq_iff comp_fun_commute split:prod.split)
kuncar@48620
  1142
qed
kuncar@48620
  1143
kuncar@48620
  1144
lemma Image_fold:
kuncar@48620
  1145
  assumes "finite R"
kuncar@48620
  1146
  shows "R `` S = Finite_Set.fold (\<lambda>(x,y) A. if x \<in> S then Set.insert y A else A) {} R"
kuncar@48620
  1147
proof -
kuncar@48620
  1148
  interpret comp_fun_commute "(\<lambda>(x,y) A. if x \<in> S then Set.insert y A else A)" 
kuncar@48620
  1149
    by (rule comp_fun_commute_Image_fold)
kuncar@48620
  1150
  have *: "\<And>x F. Set.insert x F `` S = (if fst x \<in> S then Set.insert (snd x) (F `` S) else (F `` S))"
traytel@52749
  1151
    by (force intro: rev_ImageI)
kuncar@48620
  1152
  show ?thesis using assms by (induct R) (auto simp: *)
kuncar@48620
  1153
qed
kuncar@48620
  1154
kuncar@48620
  1155
lemma insert_relcomp_union_fold:
kuncar@48620
  1156
  assumes "finite S"
kuncar@48620
  1157
  shows "{x} O S \<union> X = Finite_Set.fold (\<lambda>(w,z) A'. if snd x = w then Set.insert (fst x,z) A' else A') X S"
kuncar@48620
  1158
proof -
kuncar@48620
  1159
  interpret comp_fun_commute "\<lambda>(w,z) A'. if snd x = w then Set.insert (fst x,z) A' else A'"
kuncar@48620
  1160
  proof - 
kuncar@48620
  1161
    interpret comp_fun_idem Set.insert by (fact comp_fun_idem_insert)
kuncar@48620
  1162
    show "comp_fun_commute (\<lambda>(w,z) A'. if snd x = w then Set.insert (fst x,z) A' else A')"
wenzelm@61169
  1163
    by standard (auto simp add: fun_eq_iff split:prod.split)
kuncar@48620
  1164
  qed
kuncar@48620
  1165
  have *: "{x} O S = {(x', z). x' = fst x \<and> (snd x,z) \<in> S}" by (auto simp: relcomp_unfold intro!: exI)
kuncar@48620
  1166
  show ?thesis unfolding *
wenzelm@60758
  1167
  using \<open>finite S\<close> by (induct S) (auto split: prod.split)
kuncar@48620
  1168
qed
kuncar@48620
  1169
kuncar@48620
  1170
lemma insert_relcomp_fold:
kuncar@48620
  1171
  assumes "finite S"
kuncar@48620
  1172
  shows "Set.insert x R O S = 
kuncar@48620
  1173
    Finite_Set.fold (\<lambda>(w,z) A'. if snd x = w then Set.insert (fst x,z) A' else A') (R O S) S"
kuncar@48620
  1174
proof -
kuncar@48620
  1175
  have "Set.insert x R O S = ({x} O S) \<union> (R O S)" by auto
kuncar@48620
  1176
  then show ?thesis by (auto simp: insert_relcomp_union_fold[OF assms])
kuncar@48620
  1177
qed
kuncar@48620
  1178
kuncar@48620
  1179
lemma comp_fun_commute_relcomp_fold:
kuncar@48620
  1180
  assumes "finite S"
kuncar@48620
  1181
  shows "comp_fun_commute (\<lambda>(x,y) A. 
kuncar@48620
  1182
    Finite_Set.fold (\<lambda>(w,z) A'. if y = w then Set.insert (x,z) A' else A') A S)"
kuncar@48620
  1183
proof -
kuncar@48620
  1184
  have *: "\<And>a b A. 
kuncar@48620
  1185
    Finite_Set.fold (\<lambda>(w, z) A'. if b = w then Set.insert (a, z) A' else A') A S = {(a,b)} O S \<union> A"
kuncar@48620
  1186
    by (auto simp: insert_relcomp_union_fold[OF assms] cong: if_cong)
wenzelm@61169
  1187
  show ?thesis by standard (auto simp: *)
kuncar@48620
  1188
qed
kuncar@48620
  1189
kuncar@48620
  1190
lemma relcomp_fold:
kuncar@48620
  1191
  assumes "finite R"
kuncar@48620
  1192
  assumes "finite S"
kuncar@48620
  1193
  shows "R O S = Finite_Set.fold 
kuncar@48620
  1194
    (\<lambda>(x,y) A. Finite_Set.fold (\<lambda>(w,z) A'. if y = w then Set.insert (x,z) A' else A') A S) {} R"
traytel@52749
  1195
  using assms by (induct R)
traytel@52749
  1196
    (auto simp: comp_fun_commute.fold_insert comp_fun_commute_relcomp_fold insert_relcomp_fold
kuncar@48620
  1197
      cong: if_cong)
kuncar@48620
  1198
nipkow@1128
  1199
end