--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/Library/Order_Union.thy Mon May 27 20:09:20 2013 +0200
@@ -0,0 +1,378 @@
+(* Title: HOL/Library/Order_Union.thy
+ Author: Andrei Popescu, TU Muenchen
+
+Subset of Constructions_on_Wellorders that provides the ordinal sum but does
+not rely on the ~/HOL/Library/Zorn.thy.
+*)
+
+header {* Order Union *}
+
+theory Order_Union
+imports "~~/src/HOL/Cardinals/Wellfounded_More_Base"
+begin
+
+definition Osum :: "'a rel \<Rightarrow> 'a rel \<Rightarrow> 'a rel" (infix "Osum" 60) where
+ "r Osum r' = r \<union> r' \<union> {(a, a'). a \<in> Field r \<and> a' \<in> Field r'}"
+
+abbreviation Osum2 :: "'a rel \<Rightarrow> 'a rel \<Rightarrow> 'a rel" (infix "\<union>o" 60) where
+ "r \<union>o r' \<equiv> r Osum r'"
+
+lemma Field_Osum: "Field (r \<union>o r') = Field r \<union> Field r'"
+ unfolding Osum_def Field_def by blast
+
+lemma Osum_wf:
+assumes FLD: "Field r Int Field r' = {}" and
+ WF: "wf r" and WF': "wf r'"
+shows "wf (r Osum r')"
+unfolding wf_eq_minimal2 unfolding Field_Osum
+proof(intro allI impI, elim conjE)
+ fix A assume *: "A \<subseteq> Field r \<union> Field r'" and **: "A \<noteq> {}"
+ obtain B where B_def: "B = A Int Field r" by blast
+ show "\<exists>a\<in>A. \<forall>a'\<in>A. (a', a) \<notin> r \<union>o r'"
+ proof(cases "B = {}")
+ assume Case1: "B \<noteq> {}"
+ hence "B \<noteq> {} \<and> B \<le> Field r" using B_def by auto
+ then obtain a where 1: "a \<in> B" and 2: "\<forall>a1 \<in> B. (a1,a) \<notin> r"
+ using WF unfolding wf_eq_minimal2 by blast
+ hence 3: "a \<in> Field r \<and> a \<notin> Field r'" using B_def FLD by auto
+ (* *)
+ have "\<forall>a1 \<in> A. (a1,a) \<notin> r Osum r'"
+ proof(intro ballI)
+ fix a1 assume **: "a1 \<in> A"
+ {assume Case11: "a1 \<in> Field r"
+ hence "(a1,a) \<notin> r" using B_def ** 2 by auto
+ moreover
+ have "(a1,a) \<notin> r'" using 3 by (auto simp add: Field_def)
+ ultimately have "(a1,a) \<notin> r Osum r'"
+ using 3 unfolding Osum_def by auto
+ }
+ moreover
+ {assume Case12: "a1 \<notin> Field r"
+ hence "(a1,a) \<notin> r" unfolding Field_def by auto
+ moreover
+ have "(a1,a) \<notin> r'" using 3 unfolding Field_def by auto
+ ultimately have "(a1,a) \<notin> r Osum r'"
+ using 3 unfolding Osum_def by auto
+ }
+ ultimately show "(a1,a) \<notin> r Osum r'" by blast
+ qed
+ thus ?thesis using 1 B_def by auto
+ next
+ assume Case2: "B = {}"
+ hence 1: "A \<noteq> {} \<and> A \<le> Field r'" using * ** B_def by auto
+ then obtain a' where 2: "a' \<in> A" and 3: "\<forall>a1' \<in> A. (a1',a') \<notin> r'"
+ using WF' unfolding wf_eq_minimal2 by blast
+ hence 4: "a' \<in> Field r' \<and> a' \<notin> Field r" using 1 FLD by blast
+ (* *)
+ have "\<forall>a1' \<in> A. (a1',a') \<notin> r Osum r'"
+ proof(unfold Osum_def, auto simp add: 3)
+ fix a1' assume "(a1', a') \<in> r"
+ thus False using 4 unfolding Field_def by blast
+ next
+ fix a1' assume "a1' \<in> A" and "a1' \<in> Field r"
+ thus False using Case2 B_def by auto
+ qed
+ thus ?thesis using 2 by blast
+ qed
+qed
+
+lemma Osum_Refl:
+assumes FLD: "Field r Int Field r' = {}" and
+ REFL: "Refl r" and REFL': "Refl r'"
+shows "Refl (r Osum r')"
+using assms
+unfolding refl_on_def Field_Osum unfolding Osum_def by blast
+
+lemma Osum_trans:
+assumes FLD: "Field r Int Field r' = {}" and
+ TRANS: "trans r" and TRANS': "trans r'"
+shows "trans (r Osum r')"
+proof(unfold trans_def, auto)
+ fix x y z assume *: "(x, y) \<in> r \<union>o r'" and **: "(y, z) \<in> r \<union>o r'"
+ show "(x, z) \<in> r \<union>o r'"
+ proof-
+ {assume Case1: "(x,y) \<in> r"
+ hence 1: "x \<in> Field r \<and> y \<in> Field r" unfolding Field_def by auto
+ have ?thesis
+ proof-
+ {assume Case11: "(y,z) \<in> r"
+ hence "(x,z) \<in> r" using Case1 TRANS trans_def[of r] by blast
+ hence ?thesis unfolding Osum_def by auto
+ }
+ moreover
+ {assume Case12: "(y,z) \<in> r'"
+ hence "y \<in> Field r'" unfolding Field_def by auto
+ hence False using FLD 1 by auto
+ }
+ moreover
+ {assume Case13: "z \<in> Field r'"
+ hence ?thesis using 1 unfolding Osum_def by auto
+ }
+ ultimately show ?thesis using ** unfolding Osum_def by blast
+ qed
+ }
+ moreover
+ {assume Case2: "(x,y) \<in> r'"
+ hence 2: "x \<in> Field r' \<and> y \<in> Field r'" unfolding Field_def by auto
+ have ?thesis
+ proof-
+ {assume Case21: "(y,z) \<in> r"
+ hence "y \<in> Field r" unfolding Field_def by auto
+ hence False using FLD 2 by auto
+ }
+ moreover
+ {assume Case22: "(y,z) \<in> r'"
+ hence "(x,z) \<in> r'" using Case2 TRANS' trans_def[of r'] by blast
+ hence ?thesis unfolding Osum_def by auto
+ }
+ moreover
+ {assume Case23: "y \<in> Field r"
+ hence False using FLD 2 by auto
+ }
+ ultimately show ?thesis using ** unfolding Osum_def by blast
+ qed
+ }
+ moreover
+ {assume Case3: "x \<in> Field r \<and> y \<in> Field r'"
+ have ?thesis
+ proof-
+ {assume Case31: "(y,z) \<in> r"
+ hence "y \<in> Field r" unfolding Field_def by auto
+ hence False using FLD Case3 by auto
+ }
+ moreover
+ {assume Case32: "(y,z) \<in> r'"
+ hence "z \<in> Field r'" unfolding Field_def by blast
+ hence ?thesis unfolding Osum_def using Case3 by auto
+ }
+ moreover
+ {assume Case33: "y \<in> Field r"
+ hence False using FLD Case3 by auto
+ }
+ ultimately show ?thesis using ** unfolding Osum_def by blast
+ qed
+ }
+ ultimately show ?thesis using * unfolding Osum_def by blast
+ qed
+qed
+
+lemma Osum_Preorder:
+"\<lbrakk>Field r Int Field r' = {}; Preorder r; Preorder r'\<rbrakk> \<Longrightarrow> Preorder (r Osum r')"
+unfolding preorder_on_def using Osum_Refl Osum_trans by blast
+
+lemma Osum_antisym:
+assumes FLD: "Field r Int Field r' = {}" and
+ AN: "antisym r" and AN': "antisym r'"
+shows "antisym (r Osum r')"
+proof(unfold antisym_def, auto)
+ fix x y assume *: "(x, y) \<in> r \<union>o r'" and **: "(y, x) \<in> r \<union>o r'"
+ show "x = y"
+ proof-
+ {assume Case1: "(x,y) \<in> r"
+ hence 1: "x \<in> Field r \<and> y \<in> Field r" unfolding Field_def by auto
+ have ?thesis
+ proof-
+ have "(y,x) \<in> r \<Longrightarrow> ?thesis"
+ using Case1 AN antisym_def[of r] by blast
+ moreover
+ {assume "(y,x) \<in> r'"
+ hence "y \<in> Field r'" unfolding Field_def by auto
+ hence False using FLD 1 by auto
+ }
+ moreover
+ have "x \<in> Field r' \<Longrightarrow> False" using FLD 1 by auto
+ ultimately show ?thesis using ** unfolding Osum_def by blast
+ qed
+ }
+ moreover
+ {assume Case2: "(x,y) \<in> r'"
+ hence 2: "x \<in> Field r' \<and> y \<in> Field r'" unfolding Field_def by auto
+ have ?thesis
+ proof-
+ {assume "(y,x) \<in> r"
+ hence "y \<in> Field r" unfolding Field_def by auto
+ hence False using FLD 2 by auto
+ }
+ moreover
+ have "(y,x) \<in> r' \<Longrightarrow> ?thesis"
+ using Case2 AN' antisym_def[of r'] by blast
+ moreover
+ {assume "y \<in> Field r"
+ hence False using FLD 2 by auto
+ }
+ ultimately show ?thesis using ** unfolding Osum_def by blast
+ qed
+ }
+ moreover
+ {assume Case3: "x \<in> Field r \<and> y \<in> Field r'"
+ have ?thesis
+ proof-
+ {assume "(y,x) \<in> r"
+ hence "y \<in> Field r" unfolding Field_def by auto
+ hence False using FLD Case3 by auto
+ }
+ moreover
+ {assume Case32: "(y,x) \<in> r'"
+ hence "x \<in> Field r'" unfolding Field_def by blast
+ hence False using FLD Case3 by auto
+ }
+ moreover
+ have "\<not> y \<in> Field r" using FLD Case3 by auto
+ ultimately show ?thesis using ** unfolding Osum_def by blast
+ qed
+ }
+ ultimately show ?thesis using * unfolding Osum_def by blast
+ qed
+qed
+
+lemma Osum_Partial_order:
+"\<lbrakk>Field r Int Field r' = {}; Partial_order r; Partial_order r'\<rbrakk> \<Longrightarrow>
+ Partial_order (r Osum r')"
+unfolding partial_order_on_def using Osum_Preorder Osum_antisym by blast
+
+lemma Osum_Total:
+assumes FLD: "Field r Int Field r' = {}" and
+ TOT: "Total r" and TOT': "Total r'"
+shows "Total (r Osum r')"
+using assms
+unfolding total_on_def Field_Osum unfolding Osum_def by blast
+
+lemma Osum_Linear_order:
+"\<lbrakk>Field r Int Field r' = {}; Linear_order r; Linear_order r'\<rbrakk> \<Longrightarrow>
+ Linear_order (r Osum r')"
+unfolding linear_order_on_def using Osum_Partial_order Osum_Total by blast
+
+lemma Osum_minus_Id1:
+assumes "r \<le> Id"
+shows "(r Osum r') - Id \<le> (r' - Id) \<union> (Field r \<times> Field r')"
+proof-
+ let ?Left = "(r Osum r') - Id"
+ let ?Right = "(r' - Id) \<union> (Field r \<times> Field r')"
+ {fix a::'a and b assume *: "(a,b) \<notin> Id"
+ {assume "(a,b) \<in> r"
+ with * have False using assms by auto
+ }
+ moreover
+ {assume "(a,b) \<in> r'"
+ with * have "(a,b) \<in> r' - Id" by auto
+ }
+ ultimately
+ have "(a,b) \<in> ?Left \<Longrightarrow> (a,b) \<in> ?Right"
+ unfolding Osum_def by auto
+ }
+ thus ?thesis by auto
+qed
+
+lemma Osum_minus_Id2:
+assumes "r' \<le> Id"
+shows "(r Osum r') - Id \<le> (r - Id) \<union> (Field r \<times> Field r')"
+proof-
+ let ?Left = "(r Osum r') - Id"
+ let ?Right = "(r - Id) \<union> (Field r \<times> Field r')"
+ {fix a::'a and b assume *: "(a,b) \<notin> Id"
+ {assume "(a,b) \<in> r'"
+ with * have False using assms by auto
+ }
+ moreover
+ {assume "(a,b) \<in> r"
+ with * have "(a,b) \<in> r - Id" by auto
+ }
+ ultimately
+ have "(a,b) \<in> ?Left \<Longrightarrow> (a,b) \<in> ?Right"
+ unfolding Osum_def by auto
+ }
+ thus ?thesis by auto
+qed
+
+lemma Osum_minus_Id:
+assumes TOT: "Total r" and TOT': "Total r'" and
+ NID: "\<not> (r \<le> Id)" and NID': "\<not> (r' \<le> Id)"
+shows "(r Osum r') - Id \<le> (r - Id) Osum (r' - Id)"
+proof-
+ {fix a a' assume *: "(a,a') \<in> (r Osum r')" and **: "a \<noteq> a'"
+ have "(a,a') \<in> (r - Id) Osum (r' - Id)"
+ proof-
+ {assume "(a,a') \<in> r \<or> (a,a') \<in> r'"
+ with ** have ?thesis unfolding Osum_def by auto
+ }
+ moreover
+ {assume "a \<in> Field r \<and> a' \<in> Field r'"
+ hence "a \<in> Field(r - Id) \<and> a' \<in> Field (r' - Id)"
+ using assms Total_Id_Field by blast
+ hence ?thesis unfolding Osum_def by auto
+ }
+ ultimately show ?thesis using * unfolding Osum_def by blast
+ qed
+ }
+ thus ?thesis by(auto simp add: Osum_def)
+qed
+
+lemma wf_Int_Times:
+assumes "A Int B = {}"
+shows "wf(A \<times> B)"
+proof(unfold wf_def, auto)
+ fix P x
+ assume *: "\<forall>x. (\<forall>y. y \<in> A \<and> x \<in> B \<longrightarrow> P y) \<longrightarrow> P x"
+ moreover have "\<forall>y \<in> A. P y" using assms * by blast
+ ultimately show "P x" using * by (case_tac "x \<in> B", auto)
+qed
+
+lemma Osum_wf_Id:
+assumes TOT: "Total r" and TOT': "Total r'" and
+ FLD: "Field r Int Field r' = {}" and
+ WF: "wf(r - Id)" and WF': "wf(r' - Id)"
+shows "wf ((r Osum r') - Id)"
+proof(cases "r \<le> Id \<or> r' \<le> Id")
+ assume Case1: "\<not>(r \<le> Id \<or> r' \<le> Id)"
+ have "Field(r - Id) Int Field(r' - Id) = {}"
+ using FLD mono_Field[of "r - Id" r] mono_Field[of "r' - Id" r']
+ Diff_subset[of r Id] Diff_subset[of r' Id] by blast
+ thus ?thesis
+ using Case1 Osum_minus_Id[of r r'] assms Osum_wf[of "r - Id" "r' - Id"]
+ wf_subset[of "(r - Id) \<union>o (r' - Id)" "(r Osum r') - Id"] by auto
+next
+ have 1: "wf(Field r \<times> Field r')"
+ using FLD by (auto simp add: wf_Int_Times)
+ assume Case2: "r \<le> Id \<or> r' \<le> Id"
+ moreover
+ {assume Case21: "r \<le> Id"
+ hence "(r Osum r') - Id \<le> (r' - Id) \<union> (Field r \<times> Field r')"
+ using Osum_minus_Id1[of r r'] by simp
+ moreover
+ {have "Domain(Field r \<times> Field r') Int Range(r' - Id) = {}"
+ using FLD unfolding Field_def by blast
+ hence "wf((r' - Id) \<union> (Field r \<times> Field r'))"
+ using 1 WF' wf_Un[of "Field r \<times> Field r'" "r' - Id"]
+ by (auto simp add: Un_commute)
+ }
+ ultimately have ?thesis by (auto simp add: wf_subset)
+ }
+ moreover
+ {assume Case22: "r' \<le> Id"
+ hence "(r Osum r') - Id \<le> (r - Id) \<union> (Field r \<times> Field r')"
+ using Osum_minus_Id2[of r' r] by simp
+ moreover
+ {have "Range(Field r \<times> Field r') Int Domain(r - Id) = {}"
+ using FLD unfolding Field_def by blast
+ hence "wf((r - Id) \<union> (Field r \<times> Field r'))"
+ using 1 WF wf_Un[of "r - Id" "Field r \<times> Field r'"]
+ by (auto simp add: Un_commute)
+ }
+ ultimately have ?thesis by (auto simp add: wf_subset)
+ }
+ ultimately show ?thesis by blast
+qed
+
+lemma Osum_Well_order:
+assumes FLD: "Field r Int Field r' = {}" and
+ WELL: "Well_order r" and WELL': "Well_order r'"
+shows "Well_order (r Osum r')"
+proof-
+ have "Total r \<and> Total r'" using WELL WELL'
+ by (auto simp add: order_on_defs)
+ thus ?thesis using assms unfolding well_order_on_def
+ using Osum_Linear_order Osum_wf_Id by blast
+qed
+
+end
+