∀ {α : Type u_1} [inst : DecidableEq α] (x : Set α) (h : x ∈ Filter.cofinite.sets),
  { f := fun s => {a | a ∉ s}, pt := ∅, inf := fun x1 x2 => x1 ∪ x2, inf_le_left := ⋯, inf_le_right := ⋯ }.f
      (Set.Finite.toFinset h) ⊆
    x