English
In an R1 space, the coclosedCompact filter equals the cocompact filter.
Русский
В R1-пространстве фильтры coclosedCompact и cocompact совпадают.
LaTeX
$$coclosedCompact X = cocompact X$$
Lean4
/-- In an R₁ space, the filters `coclosedCompact` and `cocompact` are equal. -/
@[simp]
theorem coclosedCompact_eq_cocompact : coclosedCompact X = cocompact X :=
by
refine le_antisymm ?_ cocompact_le_coclosedCompact
rw [hasBasis_coclosedCompact.le_basis_iff hasBasis_cocompact]
exact fun K hK ↦ ⟨closure K, ⟨isClosed_closure, hK.closure⟩, compl_subset_compl.2 subset_closure⟩