English
The codomain and domain of a homeomorphism are locally compact simultaneously: LocallyCompactSpace X iff LocallyCompactSpace Y.
Русский
Область и областьюCode две локально компактны одновременно: LocallyCompactSpace X эквивалентно LocallyCompactSpace Y.
LaTeX
$$$LocallyCompactSpace X \\iff LocallyCompactSpace Y$$$
Lean4
/-- The codomain of a homeomorphism is a locally compact space if and only if
the domain is a locally compact space. -/
theorem locallyCompactSpace_iff (h : X ≃ₜ Y) : LocallyCompactSpace X ↔ LocallyCompactSpace Y := by
exact ⟨fun _ => h.symm.isOpenEmbedding.locallyCompactSpace, fun _ => h.isClosedEmbedding.locallyCompactSpace⟩