refine' ⟨fun h ↦ _, _⟩
α : Type u_1
β : Type u_2
ι : Type u_3
s : Set α
n : ℕ∞
f g : α → ℕ∞
⊢ ∑' (a : α), f a = ⊤ ↔ (support f).Infinite ∨ ∃ a, f a = ⊤
case refine'_1
α : Type u_1
β : Type u_2
ι : Type u_3
s : Set α
n : ℕ∞
f g : α → ℕ∞
h : ∑' (a : α), f a = ⊤
⊢ (support f).Infinite ∨ ∃ a, f a = ⊤

case refine'_2
α : Type u_1
β : Type u_2
ι : Type u_3
s : Set α
n : ℕ∞
f g : α → ℕ∞
⊢ ((support f).Infinite ∨ ∃ a, f a = ⊤) → ∑' (a : α), f a = ⊤