# Urysohn's lemma

> English word · Proper noun

## Definitions
1. A lemma stating that a topological space is normal if and only if any two disjoint closed subsets can be separated by a continuous function.

## Etymology
Named after the mathematician Pavel Samuilovich Urysohn.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/urysohn-s-lemma