---
tag: 0NW6CH38YR
kind: concept
name: T1 space
aliases: [accessible-space]
msc: [54D10]
sources:
  - url: https://en.wikipedia.org/wiki/T1_space
    locator: lead section
same_as:
  wikidata: Q284347
  wikipedia: T1 space
---

## Summary

A T1 space is a topological space in which, for any two distinct points, each one has an open set that misses the other.
Equivalently, every one-point set is closed.