proposition: Lemma not_lt_2_divides : forall n m:nat, n <> 1 -> n < 2 -> 0 < m -> ~ divides n m.
proof: Proof. intros n m H H0; cut (n=0). intro e;rewrite e. case m. intro; absurd (0 < 0); auto with arith. intros n0 Hn0 H1. elim H1; intros q Hq. rewrite Nat.mul_0_r in Hq; discriminate Hq. lia. Qed.
imports: Arith Lia