∀ {α : Type u_1} {M₀ : Type u_2} [inst : MonoidWithZero M₀] [inst_1 : PartialOrder M₀] {a : M₀} [inst_2 : Preorder α]
  {f : α → M₀} [PosMulStrictMono M₀], StrictAnti f → 0 < a → StrictAnti fun x => a * f x