Definition:Closed Locally Finite Set of Subsets

From ProofWiki
Jump to navigation Jump to search

Definition

Let $T = \struct {S, \tau}$ be a topological space.

Let $\FF$ be a set of subsets of $S$.


Then $\UU$ is closed locally finite if and only if:

$(1) \quad \forall F \in \FF: S \setminus F \in \tau$, that is, for all $F \in \FF: F$ is closed in $T$
$(2) \quad \FF$ is locally finite

Sources