binary subbase

Last-modified: 2010-07-26 (月) 17:19:26

Definition

A closed subbase S for a T_1 space X is said to be binary if for all imgtex.fcgi?%5bres=100%5d%7b$M%5csubset%20S$%7d%25.png with imgtex.fcgi?%5bres=100%5d%7b$%5ccap%20M=%5cemptyset$%7d%25.png there exist A and B in M with imgtex.fcgi?%5bres=100%5d%7b$A%5ccap%20B=%5cemptyset$%7d%25.png .

Reference

J. van Mill and E. Wattel, ''An external characterization of spaces which admit binary
normal subbase'', Amer. J. Math. 100(1978), pp987-994.