proposition: Lemma Ndiv2_bit_neq a a' : N.eqb a a' = false -> N.odd a = N.odd a' -> N.eqb (N.div2 a) (N.div2 a') = false.
proof: Proof. intros H H'. eqb2eq. contradict H. now apply Ndiv2_bit_eq. Qed.
imports: Bool Sumbool Arith BinPos BinNat Pnat Nnat Ndigits