Character (of a topological space)

From Encyclopedia of Mathematics
Jump to: navigation, search

2010 Mathematics Subject Classification: Primary: 54A25 [MSN][ZBL]

One of the cardinal characteristics of a topological space $X$. The local character $\chi(x,X)$ at a point $x \in X$ is the least cardinality of a local base at $x$. The character $\chi(X)$ is the least upper bound of the local characters.

A space satisfies the first axiom of countability if and only if it has countable character.


How to Cite This Entry:
Character (of a topological space). Encyclopedia of Mathematics. URL: