refine ⟨w 2 - w 1, w 1, funext <| fun i ↦ ?_⟩
d : ℕ
inst✝ : NeZero d
w : Weight 2 d
h : normalized w
⊢ ∃ a b, w = of_fraction d a b
d : ℕ
inst✝ : NeZero d
w : Weight 2 d
h : normalized w
i : Fin (Nat.succ 2)
⊢ w i = of_fraction d (w 2 - w 1) (w 1) i