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 go_left :
forall (p : key) (v' : data),
occ v' p (bnode n v t1 t2) -> Key.lt p n -> occ v' p t1.