Definition:Accumulation Point of Set

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Definition

Let $T$ be a topological space.

Let $A \subseteq T$.


Let $x \in T$.

$x$ is an accumulation point of $A$ if and only if:

$x \in \operatorname{cl} \left({A \setminus \left\{{x}\right\}}\right)$

where $\operatorname{cl}$ denotes the (topological) closure of a set.


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