Let be an ideal on . A mapping is called an -covering mapping provided a sequence is -converging to a point in , there is a sequence converging to a point in such that and each . In this paper we study the spaces with certain --networks and investigate the characterization of the images of metric spaces under certain -covering mappings, which prompts us to discover --networks. The following main results are obtained: (1) A space has an --network if and only if is a continuous and -covering image of a metric space. (2) A space is an --countable space if and only if is a continuous -covering and boundary -image of a metric space. (3) A space has a point-countable --network if and only if is a continuous -covering and -image of a metric space.

生成讲解博客的中文版本

生成AI智能校验的中文版本