added lemma
authornipkow
Wed, 30 Aug 2017 18:35:23 +0200
changeset 66556 2d24e2c02130
parent 66549 b8a6f9337229
child 66557 b17d41779768
added lemma
src/HOL/Library/Tree_Multiset.thy
--- a/src/HOL/Library/Tree_Multiset.thy	Tue Aug 29 17:01:11 2017 +0200
+++ b/src/HOL/Library/Tree_Multiset.thy	Wed Aug 30 18:35:23 2017 +0200
@@ -19,6 +19,9 @@
 "subtrees_mset (Node l x r) = add_mset (Node l x r) (subtrees_mset l + subtrees_mset r)"
 
 
+lemma mset_tree_empty_iff[simp]: "mset_tree t = {#} \<longleftrightarrow> t = Leaf"
+by (cases t) auto
+
 lemma set_mset_tree[simp]: "set_mset (mset_tree t) = set_tree t"
 by(induction t) auto
 
@@ -40,7 +43,6 @@
 lemma map_mirror: "mset_tree (mirror t) = mset_tree t"
 by (induction t) (simp_all add: ac_simps)
 
-
 lemma in_subtrees_mset_iff[simp]: "s \<in># subtrees_mset t \<longleftrightarrow> s \<in> subtrees t"
 by(induction t) auto