次紧空间

定义了次紧空间的概念,它是一类弱于紧性的拓扑空间.讨论了它的性质以及它与紧性、亚紧性、可数紧性、列紧性、伪紧性和Feebly紧性之间的关系.

Two Notes on Topological Groups

In this short paper, we firstly give a short proof of Birkhoff-Kakutani Theorem by Moore metrizable Theorem. Then we prove that G is a topological group if it is a paratopological group which is a dense G_δ-set in a locally feebly compact regular space X.

可数紧空间的推广

本文首先部分回答了Berri,Porter问题,然后引入了可数紧空间的一种推广-可数S(2)-θ-闭空间,并讨论了它的几个性质。