proposition: Lemma mul_0_r : forall a : nat, a * 0 =N= 0.
proof: Proof. induction a;simpl_nat;trivial. reflexivity. Qed.
imports: HoTT.Classes.interfaces.abstract_algebra HoTT.Classes.interfaces.naturals HoTT.Classes.interfaces.orders HoTT.Classes.theory.rings HoTT.Classes.orders.semirings HoTT.Classes.theory.apartness