proposition: Lemma nat_ne_0_ge_1 x : x ≠ 0 ↔ 1 ≤ x.
proof: Proof. rewrite <-pos_ge_1. now apply nat_ne_0_pos. Qed.
imports: Coq.setoid_ring.Ring MathClasses.interfaces.abstract_algebra MathClasses.interfaces.naturals MathClasses.interfaces.orders MathClasses.orders.rings MathClasses.orders.nat_int