Top > star of the point x with respect to U
HTML convert time to 0.002 sec.


star of the point x with respect to U

Last-modified: 2011-01-20 (木) 01:32:33

Definition Edit

  • Let imgtex.fcgi?%5bres=100%5d%7b%5c%5b%20U=%5c%7bU_s%5c%7d_%7bs%5cin%20S%7d%20%5c%5d%7d%25.png be a cover of a set X and x be a point in X. The star of a one-point set {x} with respect to U (, that is, imgtex.fcgi?%5bres=100%5d%7b%5c%5b%20St%28%5c%7bx%5c%7d%2cU%29=%5ccup%5c%7bU_s%5c%2c%7c%5c%2c%5c%7bx%5c%7d%5ccap%20U_s%5cneq%5cemptyset%5c%7d%20%5c%5d%7d%25.png) is called the star of the point x with respect to U and is denoted by imgtex.fcgi?%5bres=100%5d%7b%5c%5b%20St%28x%2c%5c%2cU%29%20%5c%5d%7d%25.png.

Reference Edit

  • Engelking, Ryszard, General topology., Translated from the Polish by the author. Second edition. Sigma Series in Pure Mathematics, 6. Heldermann Verlag, Berlin, 1989. viii+529 pp. ISBN: 3-88538-006-4.