English
A linear order equipped with the order topology is a completely normal Hausdorff topological space.
Русский
Линейный порядок с порядковой топологией образует полностью нормальное Гейзенберговое (Гауссово) топологическое пространство безусловно нормированное.
LaTeX
$$CompletelyNormalSpace X$$
Lean4
/-- A linear order with order topology is a completely normal Hausdorff topological space. -/
instance (priority := 100) completelyNormalSpace : CompletelyNormalSpace X :=
⟨fun s t h₁ h₂ =>
Filter.disjoint_iff.2
⟨ordT5Nhd s t, ordT5Nhd_mem_nhdsSet h₂, ordT5Nhd t s, ordT5Nhd_mem_nhdsSet h₁.symm, disjoint_ordT5Nhd⟩⟩