changeset 72313 | babd74b71ea8 |
parent 69655 | 2b56cbb02e8a |
child 72566 | 831f17da1aab |
--- a/src/HOL/Library/Tree.thy Sat Sep 26 17:04:51 2020 +0200 +++ b/src/HOL/Library/Tree.thy Sat Sep 26 18:59:12 2020 +0200 @@ -153,6 +153,9 @@ lemma neq_empty_subtrees[simp]: "{} \<noteq> subtrees t" by (cases t)(auto) +lemma size_subtrees: "s \<in> subtrees t \<Longrightarrow> size s \<le> size t" +by(induction t)(auto) + lemma set_treeE: "a \<in> set_tree t \<Longrightarrow> \<exists>l r. \<langle>l, a, r\<rangle> \<in> subtrees t" by (induction t)(auto)