proposition: Lemma lognat_double_eq : forall a b (pf1: 2 * a <> 0)(pf2: 2 * b <> 0)(pf3 : a <> 0) (pf4: b <> 0), lognat pf3 = lognat pf4 -> lognat pf1 = lognat pf2.
proof: Proof. intros. rewrite <- (lognat_prod_sum pf3). rewrite <- (lognat_prod_sum pf4). lia. Qed.
imports: ZArith micromega.Lia