proposition: Lemma mult_a_0 : forall a, a * zero = zero.
proof: Proof. induction a as [|a1 IHa1 n a2 IHa2]; [reflexivity| now destruct a1]. Qed.
imports: Coq(Arith Max Bool Lia Compare_dec Relations Ensembles Wellfounded Bool RelationClasses Operators_Properties ArithRing Logic.Eqdep_dec) hydras(More_Arith Restriction DecPreOrder) hydras(OrdNotations)