e/Excluded point topology

Information
has gloss	eng: In mathematics, the excluded point topology is a topological structure where exclusion of a particular point defines openness. Let X be any set and p\in X. A proper subset of X is open if and only if it does not contain p. There are a variety of cases which are individually named:
lexicalization	eng: excluded point topology
instance of	(noun) (mathematics) any set of points that satisfy a set of postulates of some kind; "assume that the topological space is finite dimensional" mathematical space, topological space