diff -r 4a15873c4ec9 -r 41ee3bfccb4d src/HOL/BNF/Examples/Derivation_Trees/Prelim.thy
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/BNF/Examples/Derivation_Trees/Prelim.thy	Tue Oct 16 13:09:46 2012 +0200
@@ -0,0 +1,67 @@
+(*  Title:      HOL/BNF/Examples/Infinite_Derivation_Trees/Prelim.thy
+    Author:     Andrei Popescu, TU Muenchen
+    Copyright   2012
+
+Preliminaries.
+*)
+
+header {* Preliminaries *}
+
+theory Prelim
+imports "../../BNF"
+begin
+
+declare fset_to_fset[simp]
+
+lemma fst_snd_convol_o[simp]: "<fst o s, snd o s> = s"
+apply(rule ext) by (simp add: convol_def)
+
+abbreviation sm_abbrev (infix "\<oplus>" 60)
+where "f \<oplus> g \<equiv> Sum_Type.sum_map f g"
+
+lemma sum_map_InlD: "(f \<oplus> g) z = Inl x \<Longrightarrow> \<exists>y. z = Inl y \<and> f y = x"
+by (cases z) auto
+
+lemma sum_map_InrD: "(f \<oplus> g) z = Inr x \<Longrightarrow> \<exists>y. z = Inr y \<and> g y = x"
+by (cases z) auto
+
+abbreviation sum_case_abbrev ("[[_,_]]" 800)
+where "[[f,g]] \<equiv> Sum_Type.sum_case f g"
+
+lemma inj_Inl[simp]: "inj Inl" unfolding inj_on_def by auto
+lemma inj_Inr[simp]: "inj Inr" unfolding inj_on_def by auto
+
+lemma Inl_oplus_elim:
+assumes "Inl tr \<in> (id \<oplus> f) ` tns"
+shows "Inl tr \<in> tns"
+using assms apply clarify by (case_tac x, auto)
+
+lemma Inl_oplus_iff[simp]: "Inl tr \<in> (id \<oplus> f) ` tns \<longleftrightarrow> Inl tr \<in> tns"
+using Inl_oplus_elim
+by (metis id_def image_iff sum_map.simps(1))
+
+lemma Inl_m_oplus[simp]: "Inl -` (id \<oplus> f) ` tns = Inl -` tns"
+using Inl_oplus_iff unfolding vimage_def by auto
+
+lemma Inr_oplus_elim:
+assumes "Inr tr \<in> (id \<oplus> f) ` tns"
+shows "\<exists> n. Inr n \<in> tns \<and> f n = tr"
+using assms apply clarify by (case_tac x, auto)
+
+lemma Inr_oplus_iff[simp]:
+"Inr tr \<in> (id \<oplus> f) ` tns \<longleftrightarrow> (\<exists> n. Inr n \<in> tns \<and> f n = tr)"
+apply (rule iffI)
+ apply (metis Inr_oplus_elim)
+by (metis image_iff sum_map.simps(2))
+
+lemma Inr_m_oplus[simp]: "Inr -` (id \<oplus> f) ` tns = f ` (Inr -` tns)"
+using Inr_oplus_iff unfolding vimage_def by auto
+
+lemma Inl_Inr_image_cong:
+assumes "Inl -` A = Inl -` B" and "Inr -` A = Inr -` B"
+shows "A = B"
+apply safe using assms apply(case_tac x, auto) by(case_tac x, auto)
+
+
+
+end
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