Skip to content
EntityQ326908· pop 35· linked from 539 articles

Hausdorff space

Sign in to save

Also known as separated space, T₂ space, T2 space

topological space in which distinct points have disjoint neighbourhoods

Key facts

T 0
(Kolmogorov)
T 1
(Fréchet)
T 2
(Hausdorff)
Completely t 2
(completely Hausdorff)
T 3
(regular Hausdorff)
T 4
(normal Hausdorff)
T 5
(completely normal, Hausdorff)
T 6
(perfectly normal, Hausdorff)

via Wikipedia infobox

~13 min read

Encyclopedic overview

In topology and related branches of mathematics, a Hausdorff space (/ˈhaʊsdɔːrf/ HOWSS-dorf, /ˈhaʊzdɔːrf/ HOWZ-dorf), T2 space or separated space, is a topological space where distinct points have disjoint neighbourhoods. Of the many separation axioms that can be imposed on a topological space, the "Hausdorff condition" (T2) is the most frequently used and discussed. It implies the uniqueness of limits of sequences, nets, and filters.

Hausdorff spaces are named after Felix Hausdorff, one of the founders of topology. Hausdorff's original definition of a topological space (in 1914) included the Hausdorff condition as an axiom.

Excerpted from Wikipedia’s “Hausdorff space” article, available under the CC BY-SA 4.0 licence.