proposition: Lemma wmult_neut_r: forall (sz : nat) (x : word sz), x ^* $0 = $0.
proof: Proof. intros. unfold wmult. unfold wordBin. do 2 rewrite wordToN_nat. rewrite <- Nnat.Nat2N.inj_mul. rewrite roundTrip_0. rewrite Nat.mul_0_r. simpl. rewrite wzero'_def. reflexivity. Qed.
imports: Coq.Classes.Morphisms Coq.Classes.Morphisms_Prop Coq.Classes.Equivalence Coq.Arith.PeanoNat Coq.ZArith.BinInt  Coq.Arith.Arith Coq.NArith.NArith Coq.Bool.Bool Coq.ZArith.ZArith Coq.Logic.Eqdep_dec Coq.Logic.EqdepFacts Coq.Program.Tactics Coq.Program.Equality Coq.setoid_ring.Ring Coq.setoid_ring.Ring_polynom bbv.Nomega bbv.ZLib bbv.NatLib bbv.NLib bbv.N_Z_nat_conversions bbv.DepEq bbv.DepEqNat bbv.ReservedNotations Coq.micromega.Lia