proposition: Lemma int_abs_ne_0 x : int_abs Z N x <> 0 <-> x <> 0.
proof: Proof. destruct (int_abs_0_alt x). split;intros E1 E2;auto. Qed.
imports: HoTT.Classes.interfaces.naturals HoTT.Classes.interfaces.abstract_algebra HoTT.Classes.interfaces.orders HoTT.Classes.orders.nat_int HoTT.Classes.theory.integers HoTT.Classes.theory.rings HoTT.Classes.theory.groups HoTT.Classes.orders.rings