Not insulated

In Topologie, a point X of a topological Espace E is known as insulated if the singleton \ {X \} \, \! is a Ouvert.

Other equivalent formulations:

  • \ {X \} \, \! is a vicinity of X ;
  • X is not adherent with E - \ {X \} \, \! .

Example: in topological space \ {0 \} \ cup \, \! provided with natural topology, item 0 is isolated.

A topological space in which any point is isolated is known as discrete.

Random links:Persépolis | Hall Varian | Mastère specialized in engineering production and infrastructures in open systems | Camp of Royallieu | Annihilation electron-positrons | Noble,_l'Illinois