proposition: Lemma int_abs_1 : int_abs Z N 1 = 1.
proof: Proof. apply (injective f). rewrite (preserves_1 (f:=f)). apply int_abs_nonneg; solve_propholds. 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