|
In mathematics, Fort space, named after M. K. Fort, Jr., is an example in the theory of topological spaces. Let ''X'' be an infinite set of points, of which ''P'' is one. Then a Fort space is defined by ''X'' together with all subsets ''A'' such that: *''A'' excludes ''P'', or *''A'' contains all but a finite number of the points of ''X'' ''X'' is homeomorphic to the one-point compactification of a discrete space. Modified Fort space is similar but has two particular points ''P'' and ''Q''. So a subset is declared "open" if: *''A'' excludes ''P'' and ''Q'', or *''A'' contains all but a finite number of the points of ''X'' Fortissimo space is defined as follows. Let ''X'' be an uncountable set of points, of which ''P'' is one. A subset ''A'' is declared "open" if: *''A'' excludes ''P'', or *''A'' contains all but a countable set of the points of ''X'' ==See also== *Arens–Fort space *Appert topology *Cofinite topology *Excluded point topology 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Fort space」の詳細全文を読む スポンサード リンク
|