English
If f is continuous, injective, and a closed map, then f is a closed embedding.
Русский
Если f непрерывно, инъективно и замкнутое отображение, то f — замкнутое вложение.
LaTeX
$$$\mathrm{Continuous}(f) \land \mathrm{Injective}(f) \land \mathrm{IsClosedMap}(f) \Rightarrow \mathrm{IsClosedEmbedding}(f)$$$
Lean4
theorem of_continuous_injective_isClosedMap (h₁ : Continuous f) (h₂ : Injective f) (h₃ : IsClosedMap f) :
IsClosedEmbedding f := by
refine .of_isEmbedding_isClosedMap ⟨⟨?_⟩, h₂⟩ h₃
refine h₁.le_induced.antisymm fun s hs => ?_
refine ⟨(f '' sᶜ)ᶜ, (h₃ _ hs.isClosed_compl).isOpen_compl, ?_⟩
rw [preimage_compl, preimage_image_eq _ h₂, compl_compl]