essential derived set

Last-modified: 2011-06-05 (日) 00:35:46

Definition

  • Let x be a point of a topological space (X,τ). The essential derived set of x is the set imgtex.fcgi?%5bres=100%5d%7b%5c%5b%20%5crm%7bD%7d%5c%7bx%5c%7d=%5crm%7bcl%7d%28%5c%7bx%5c%7d%29%5csetminus%5crm%7bker%7d%28x%29%20%5c%5d%7d%25.png

Reference

  • Guia, Josep, Axioms weaker than R0., (Serbo-Croatian summary), Mat. Vesnik 36 (1984), no. 3, 195–205.