proposition: Theorem mul_assoc : ∀ n m p, n * (m * p) = n * m * p.
proof: Proof. intros n m p. destruct n as [n| ]; [ simpl | reflexivity ]. destruct m as [m| ]; [ simpl | reflexivity ]. destruct p as [p| ]; [ rewrite Nat.mul_assoc; reflexivity | reflexivity ]. Qed.
imports: Utf8 Compare_dec NPeano Misc