proposition: Lemma wminus_minus : forall sz (a b : word sz), b <= a -> wordToNat (a ^- b) = wordToNat a - wordToNat b.
proof: Proof. intros. rewrite wminus_Alt. rewrite wminus_Alt2; auto. unfold wordBinN. eapply wordToNat_natToWord_idempotent'. apply lt_minus. apply wle_le; auto. apply wordToNat_bound. apply wordToNat_bound. 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