kernel

Definition

• Let x be a point of a topological space (X,τ). The set of all y for which is not weakly separated from x is called the kernel of x.

Reference

• Aull, Charles E.; Thron, W.J., Separation axioms between T0 and T1., (English) [J] Nederl. Akad. Wet., Proc., Ser. A 65, 26-37 (1962).