English
A lemma about membership in a cone's closure: a belongs to closure(K) iff a ∈ closure of K.
Русский
Лемма про членство в замкнутом конусе: a ∈ closure(K) тогда и только тогда, когда a ∈ closure(coe(K)).
LaTeX
$$a ∈ K.closure ↔ a ∈ closure (K : Set E)$$
Lean4
instance canLift : CanLift (ConvexCone 𝕜 E) (ProperCone 𝕜 E) (↑) fun C ↦ (C : Set E).Nonempty ∧ IsClosed (C : Set E)
where prf C hC := ⟨⟨C.toPointedCone <| .of_nonempty_of_isClosed hC.1 hC.2, hC.2⟩, rfl⟩