# HG changeset patch
# User huffman
# Date 1333535158 -7200
# Node ID 95846613e414fcfaa26c204eb76203d98e5e3d8e
# Parent  fc7de207e488560eb3bc5dc08e57978c0b43fff8
update keywords file

diff -r fc7de207e488 -r 95846613e414 etc/isar-keywords.el
--- a/etc/isar-keywords.el	Wed Apr 04 14:27:20 2012 +0200
+++ b/etc/isar-keywords.el	Wed Apr 04 12:25:58 2012 +0200
@@ -129,6 +129,7 @@
     "lemma"
     "lemmas"
     "let"
+    "lift_definition"
     "linear_undo"
     "local_setup"
     "locale"
@@ -570,6 +571,7 @@
     "instance"
     "interpretation"
     "lemma"
+    "lift_definition"
     "nominal_inductive"
     "nominal_inductive2"
     "nominal_primrec"
diff -r fc7de207e488 -r 95846613e414 src/HOL/Lifting.thy
--- a/src/HOL/Lifting.thy	Wed Apr 04 14:27:20 2012 +0200
+++ b/src/HOL/Lifting.thy	Wed Apr 04 12:25:58 2012 +0200
@@ -252,6 +252,16 @@
   shows "equivp (op=::'a\<Rightarrow>'a\<Rightarrow>bool)"
 by (rule identity_equivp)
 
+lemma typedef_to_Quotient:
+  assumes "type_definition Rep Abs {x. P x}"
+  and T_def: "T \<equiv> (\<lambda>x y. x = Rep y)"
+  shows "Quotient (invariant P) Abs Rep T"
+proof -
+  interpret type_definition Rep Abs "{x. P x}" by fact
+  from Rep Abs_inject Rep_inverse Abs_inverse T_def show ?thesis
+    by (auto intro!: QuotientI simp: invariant_def fun_eq_iff)
+qed
+
 lemma invariant_type_to_Quotient:
   assumes "type_definition Rep Abs {x. P x}"
   and T_def: "T \<equiv> (\<lambda>x y. (invariant P) x x \<and> Abs x = y)"