Definition 5.4.3 (Cauchy Filter). Let $(X, \fU)$ be a uniform space and $\fF \subset 2^{X}$ be a filter on $X$, then $\fF$ is Cauchy if for every $V \in \fU$, there exists $E \in \fF$ such that $E$ is $V$-small.
Definition 5.4.3 (Cauchy Filter). Let $(X, \fU)$ be a uniform space and $\fF \subset 2^{X}$ be a filter on $X$, then $\fF$ is Cauchy if for every $V \in \fU$, there exists $E \in \fF$ such that $E$ is $V$-small.