| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 5777944 | Topology and its Applications | 2017 | 13 Pages |
Abstract
A filter F on Ï is called Fréchet-Urysohn if the space with only one non-isolated point Ïâª{F} is a Fréchet-Urysohn space, where the neighborhoods of the non-isolated point are determined by the elements of F. In this paper, we distinguish some Fréchet-Urysohn filters by using two pre-orderings of filters: One is the Rudin-Keisler pre-order and the other one was introduced by TodorÄeviÄ-Uzcátegui in [11]. We mainly construct an RK-chain of size c+ which is RK-above of every FU-filter. Also, we show that there is an infinite RK-antichain of FU-filters.
Related Topics
Physical Sciences and Engineering
Mathematics
Geometry and Topology
Authors
S. Garcia-Ferreira, J.E. Rivera-Gómez,