English
An Alexandrov-discrete space is isomorphic to the upper set topology of its specialization order.
Русский
Пространство Александрова-дискретности изоморфно верхнему множеству топологии специализации.
LaTeX
$$$\text{homeoWithUpperSetTopologyorderIso}(\alpha)$ is a Homeomorph between $\alpha$ and $\text{WithUpperSet}(\operatorname{Specialization}(\alpha))$.$$
Lean4
/-- Sends a topological space to its specialisation order. -/
@[simps]
def topToPreord : TopCat ⥤ Preord where
obj X := .of <| Specialization X
map f := Preord.ofHom <| Specialization.map f.hom