have : ∀ m, 2*m &&& 1 = 0 := by intros; rw [Nat.land_one, Nat.mul_mod_right]
n : Nat
this : 2 * succ n - 1 = 2 * (succ n - 1) + 1
k l : Nat
⊢ 2 * k &&& 2 * l + 1 = 2 * k &&& 2 * l
n : Nat
this✝ : 2 * succ n - 1 = 2 * (succ n - 1) + 1
k l : Nat
this : ∀ (m : Nat), 2 * m &&& 1 = 0
⊢ 2 * k &&& 2 * l + 1 = 2 * k &&& 2 * l