proposition: Lemma split_cons_let : forall x y l, split ((x,y)::l) = let '(r,s) := split l in (x::r, y::s).
proof: Proof. Proof using. auto. Qed.
imports: Coq.Classes.Morphisms TLC(LibTactics LibLogic LibReflect LibOperation LibProd LibOption LibNat LibInt LibWf LibMonoid LibRelation)