Instituto de Matemáticas, Ciudad Universitaria (UNAM), D. F. 04510, México ; Department of Mathematics and Statistics, University of Calgary, Calgary, Alberta, Canada T2N 1N4
Abstract:
The property may be generalized by using filters on in a very natural way. We analyze the necessary requirements for a space to have property for a filter . We construct special filters for which has the property, in particular a P-point and a Q-point.