---
tag: 09S8DV34Y0
kind: concept
name: Subbasis
aliases: [subbase, prebase]
msc: [54A05]
sources:
  - url: https://en.wikipedia.org/wiki/Subbase
    locator: lead section
same_as:
  wikidata: Q2739990
  wikipedia: Subbase
---

## Summary

A subbasis of a topology is a family of open sets that generates the topology. The topology is the smallest one in which all members of the family are open.
The finite intersections of members of a subbasis form a basis.