ring
case mk.mk.mk
z✝² w✝² z✝¹ w✝¹ z✝ w✝ : ℤ
⊢ { z := z✝² * (z✝¹ + z✝) - 2 * w✝² * (w✝¹ + w✝), w := z✝² * (w✝¹ + w✝) + w✝² * (z✝¹ + z✝) + w✝² * (w✝¹ + w✝) } =
    { z := z✝² * z✝¹ - 2 * w✝² * w✝¹ + (z✝² * z✝ - 2 * w✝² * w✝),
      w := z✝² * w✝¹ + w✝² * z✝¹ + w✝² * w✝¹ + (z✝² * w✝ + w✝² * z✝ + w✝² * w✝) }
no goals