# Subbase

From Encyclopedia of Mathematics

2020 Mathematics Subject Classification: *Primary:* 54A05 [MSN][ZBL]

*pre-base*

A family $\gamma$ of open subsets of a topological space $X$ such that the totality of all sets which are intersections of a finite number of elements of $\gamma$ forms a base of $X$.

#### References

[a1] | R. Engelking, "General topology" , Heldermann (1989) |

**How to Cite This Entry:**

Subbase.

*Encyclopedia of Mathematics.*URL: http://encyclopediaofmath.org/index.php?title=Subbase&oldid=39441

This article was adapted from an original article by M.I. Voitsekhovskii (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article