Definition:Set of Condensation Points

Definition
Let $T = \left({S, \tau}\right)$ be a topological space.

Let $A$ be a subset of $S$.

The set of condensation points of $A$ is the set of all condensation points of $A$,
 * $A^0 = \left\{{x \in S:x}\right.$ is condensation point of $\left.{A}\right\}$