proposition: Lemma below_node {elt} x h l y (e:elt) r : x < Node h l y e r <-> x < l /\ x < y /\ x < r.
proof: Proof. apply allkeys_node. now intros ? ? ->. Qed.
imports: Coq(Bool Arith BinInt FunInd) Coq(Orders OrdersFacts OrdersLists) MMaps(Comparisons Interface OrdList)