no goals
ι : Type ?u.28024
α : Type u_1
β : Type ?u.28030
γ : Type ?u.28033
inst✝² : TopologicalSpace α
inst✝¹ : TopologicalSpace β
inst✝ : TopologicalSpace γ
U : Opens α
⊢ ¬Set.Nonempty ↑U ↔ U = ⊥
rw [← coe_inj, coe_bot, ← Set.not_nonempty_iff_eq_empty]