In this paper, by msss_mappings, the relations between metric spaces and spaces with σ _locally countable cs_networks or spaces with σ _locally countable weak bases are established. These are some answers to A...In this paper, by msss_mappings, the relations between metric spaces and spaces with σ _locally countable cs_networks or spaces with σ _locally countable weak bases are established. These are some answers to Alexandroff’s problems.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Foundation item: Supported by the NSF of Fujian(Z0511033)Supported by the Eduction Committee of Fujian(JB04298)Supported by the Eduction Committee of Henan (2004606018, 200510483002)
文摘In this paper, we prove that a space with a compact Countable weak base if and only if it is a weak open cs-image of a metric space.
文摘In this paper, by msss_mappings, the relations between metric spaces and spaces with σ _locally countable cs_networks or spaces with σ _locally countable weak bases are established. These are some answers to Alexandroff’s problems.
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.
