rw [h]
case succ.inr
n : ℕ
hn : 2 ≤ n + 1
h2 : n ≥ 2
h : ∏ x ∈ Ico 1 (n + 1), (↑x + 1) = (↑n + 1) * ∏ x ∈ Ico 1 (n + 1), ↑x
⊢ (∏ x ∈ Ico 1 (n + 1), (↑x + 1)) * (↑n + 1 + 1) = (↑n + 1 + 1) * ((∏ x ∈ Ico 1 (n + 1), ↑x) * (↑n + 1))
case succ.inr
n : ℕ
hn : 2 ≤ n + 1
h2 : n ≥ 2
h : ∏ x ∈ Ico 1 (n + 1), (↑x + 1) = (↑n + 1) * ∏ x ∈ Ico 1 (n + 1), ↑x
⊢ ((↑n + 1) * ∏ x ∈ Ico 1 (n + 1), ↑x) * (↑n + 1 + 1) = (↑n + 1 + 1) * ((∏ x ∈ Ico 1 (n + 1), ↑x) * (↑n + 1))