*** empty log message ***

--- a/src/HOL/Map.thy	Wed May 14 10:22:09 2003 +0200
+++ b/src/HOL/Map.thy	Wed May 14 10:33:52 2003 +0200
@@ -201,6 +201,11 @@
 apply(simp add: map_add_def split:option.split)
 done
 
+lemma map_add_comm: "dom m1 \<inter> dom m2 = {} \<Longrightarrow> m1++m2 = m2++m1"
+apply(rule ext)
+apply(fastsimp simp:map_add_def split:option.split)
+done
+
 lemma map_add_Some_iff: 
  "((m ++ n) k = Some x) = (n k = Some x | n k = None & m k = Some x)"
 apply (unfold map_add_def)