simp_rw [mul_ite, mul_zero, ←sum_filter]
P h : ℕ
x : ℝ
hx : 1 ≤ x
hP : Squarefree P
⊢ (∑ d ∈ P.divisors, if ↑d ≤ x then ↑h ^ ω d else 0) ≤ ∑ d ∈ P.divisors, x * if ↑d ≤ x then ↑h ^ ω d / ↑d else 0
P h : ℕ
x : ℝ
hx : 1 ≤ x
hP : Squarefree P
⊢ ∑ a ∈ filter (fun a => ↑a ≤ x) P.divisors, ↑h ^ ω a ≤ ∑ a ∈ filter (fun a => ↑a ≤ x) P.divisors, x * (↑h ^ ω a / ↑a)