---
tag: 03HMJASQBQ
kind: concept
name: Regular space
aliases: [t3-space]
msc: [54D15]
sources:
  - url: https://en.wikipedia.org/wiki/Regular_space
    locator: lead section
same_as:
  wikidata: Q1193403
  wikipedia: Regular space
---

## Summary

A topological space is regular when each closed set and each point outside it lie in disjoint open sets.