tags:definition |topology

Open Ball

Context

Statements

Definition (@Tu11, pp. 317, @Eck23, Definition 1.1). Let $(X,d)$ be a metric space. For any $p\in X$ and $r>0$, the set $B_{<r}(p)=\{x\in X|m(x,p)<r\}$ is said to be an open ball with center $p$ and radius $r$.

References