|
|||||
|
|
Dually discrete spaces |
|
| Authors: | Ofelia T. Alas |
| Affiliation: | a Instituto de Matemática e Estatística, Universidade de São Paulo, Caixa Postal 66281, 05314-970 São Paulo, Brazil b Departamento de Matemáticas, Universidad Autónoma Metropolitana, Unidad Iztapalapa, Avenida San Rafael Atlixco, #186, Apartado Postal 55-532, 09340 México, D.F., Mexico |
| Abstract: | A neighbourhood assignment in a space X is a family  of open subsets of X such that x∈Ox for any x∈X. A set Y⊆X is a kernel ofO if  . We obtain some new results concerning dually discrete spaces, being those spaces for which every neighbourhood assignment has a discrete kernel. This is a strictly larger class than the class of D-spaces of [E.K. van Douwen, W.F. Pfeffer, Some properties of the Sorgenfrey line and related spaces, Pacific J. Math. 81 (2) (1979) 371-377]. |
| Keywords: | primary, 54D20 secondary, 54G99 |
| 本文献已被 ScienceDirect 等数据库收录！ | |