In this paper, we mainly discuss the images of certain spaces under closed sequencecovering maps. It is showed that the property with a locally countable weak base is preserved by closed sequence-covering maps. And th...In this paper, we mainly discuss the images of certain spaces under closed sequencecovering maps. It is showed that the property with a locally countable weak base is preserved by closed sequence-covering maps. And the following question is discussed： Are the closed sequence-covering images of spaces with a point-countable sn-network sn-first countable？展开更多
In this paper, we give some characterizations of N-spaces by mssc-images ofmetric spaces, and prove that a space X is an N-space if and only if X is a sequence-covering (sequentially quotient) mssc-image of a metric s...In this paper, we give some characterizations of N-spaces by mssc-images ofmetric spaces, and prove that a space X is an N-space if and only if X is a sequence-covering (sequentially quotient) mssc-image of a metric space, which answer a conjectureon N-spaces affirmatively.展开更多
基金Supported by National Natural Science Foundation of China (Grant Nos.1120141410971185+2 种基金11171162)the Natural Science Foundation of Fujian Province (Grant No.2012J05013)Training Programme Foundation for Excellent Youth Researching Talents of Fujian’s Universities (Grant No.JA13190)
文摘In this paper, we mainly discuss the images of certain spaces under closed sequencecovering maps. It is showed that the property with a locally countable weak base is preserved by closed sequence-covering maps. And the following question is discussed： Are the closed sequence-covering images of spaces with a point-countable sn-network sn-first countable？
基金Supported by NSF of the Education Committee of Jiangsu Province in China (02KJB110001)
文摘In this paper, we give some characterizations of N-spaces by mssc-images ofmetric spaces, and prove that a space X is an N-space if and only if X is a sequence-covering (sequentially quotient) mssc-image of a metric space, which answer a conjectureon N-spaces affirmatively.
