Definition:Adherent Point/Definition 1

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

Let $A \subseteq X$.

A point $x \in X$ is an adherent point of $A$ every open neighborhood $U$ of $x$ satisfies:
 * $A \cap U \ne \varnothing$

Also see

 * Definition:Condensation Point
 * Definition:Limit Point of Set
 * Definition:Omega-Accumulation Point


 * Relationship between Limit Point Types