Hausdorff space
preferred label: فضای هاسدورف @fa
type: Concept
related: Urysohn lemma

Tietze extension theorem
preferred label: قضیه توسیع تیتز @fa
type: Concept
related: Urysohn lemma

closed set
preferred label: مجموعه بسته @fa
type: Concept
related: Urysohn lemma

Urysohn lemma
related: closed set
related: Tietze extension theorem
related: Hausdorff space
broader: normal space
preferred label: لم اوریسون @fa
type: Concept

normal space
preferred label: فضای نرمال @fa
type: Concept
narrower: Urysohn lemma