exact fun q _ => pow_ne_zero _ (ne_of_gt (Nat.pos_of_mem_factors (List.mem_toFinset.mp q.2)))
case pos
M : ℕ
hM : M ≠ 0
f : ArithmeticFunction ℝ
hf : CompletelyMultiplicative f
d : ℕ
hd : Squarefree d
i : (a : (a : ℕ) → a ∈ d.primeFactors → ℕ) → (a ∈ d.primeFactors.pi fun p => Finset.Icc 1 M) → ℕ :=
  fun a x => ∏ p ∈ d.primeFactors.attach, ↑p ^ a ↑p ⋯
a : (a : ℕ) → a ∈ d.primeFactors → ℕ
ha : a ∈ d.primeFactors.pi fun p => Finset.Icc 1 M
p : ℕ
hp : p ∈ d.primeFactors
⊢ ∀ x ∈ d.primeFactors.attach, ↑x ^ a ↑x ⋯ ≠ 0
no goals