α : Type u
β : Type v
ι : Sort w
a : α
s✝ s₁ s₂ t : Set α
p p₁ p₂ : α → Prop
inst✝ : TopologicalSpace α
s : Set α
⊢ ⋂₀ {t | IsClosed t ∧ s ⊆ t} = ⋂₀ {s_1 | IsOpen (s_1ᶜ) ∧ s_1ᶜ ⊆ sᶜ}
α : Type u
β : Type v
ι : Sort w
a : α
s✝ s₁ s₂ t : Set α
p p₁ p₂ : α → Prop
inst✝ : TopologicalSpace α
s : Set α
⊢ closure s = interior (sᶜ)ᶜ
rw [interior, closure, compl_sUnion, compl_image_set_of]
no goals
α : Type u
β : Type v
ι : Sort w
a : α
s✝ s₁ s₂ t : Set α
p p₁ p₂ : α → Prop
inst✝ : TopologicalSpace α
s : Set α
⊢ ⋂₀ {t | IsClosed t ∧ s ⊆ t} = ⋂₀ {s_1 | IsOpen (s_1ᶜ) ∧ s_1ᶜ ⊆ sᶜ}
simp only [compl_subset_compl, isOpen_compl_iff]