Definition:Excluded Point Topology/Countable

Definition
Let $S$ be a set which is non-empty.

Let $p \in S$ be some particular point of $S$.

Let $T = \struct {S, \tau_{\bar p} }$ be the excluded point space on $S$ by $p$.

Let $S$ be countably infinite.

Then $\tau_{\bar p}$ is a countable excluded point topology, and $\struct {S, \tau_{\bar p} }$ is a countable excluded point space.

Also see

 * Definition:Finite Excluded Point Topology:
 * Definition:Uncountable Excluded Point Topology