Isolated point

Point of a subset S around which there are no other points of S

In mathematics, a point x is called an isolated point of a subset S if x is an element of S and there exists a neighborhood of x that does not contain any other points of S. This is equivalent to saying that the singleton {x} is an open set in the topological space S. Another equivalent formulation is: an element x of S is an isolated point of S if and only if it is not a limit point of S.

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