Hint Resolve min_not_occ: searchtrees.
(* technical lemmas about some non-leaf search tree *)
Section search_tree_basic_properties.
Variables (n : key) (v : data) (t1 t2 : btree).
Hypothesis se : search_tree (bnode n v t1 t2).

Lemma search_tree_l : search_tree t1.
Hint Resolve search_tree_l: searchtrees.