A note on -metrizable spaces
In this paper, the relationships between metric spaces and -metrizable spaces are established in terms of certain quotient mappings, which is an answer to Alexandroff’s problems.
In this paper, the relationships between metric spaces and -metrizable spaces are established in terms of certain quotient mappings, which is an answer to Alexandroff’s problems.
In this note we study the relation between -spaces and -spaces and prove that a -space with a -hereditarily closure-preserving -network consisting of compact subsets is a -space, and that a -space with a point-countable -network consisting of compact subsets need not be a -space.
The concepts of -systems, -networks and -covers were defined by A. Arhangel’skiǐ in 1964, P. O’Meara in 1971 and R. McCoy, I. Ntantu in 1985, respectively. In this paper the relationships among -systems, -networks and -covers are further discussed and are established by -systems. As applications, some new characterizations of quotients or closed images of locally compact metric spaces are given by means of -systems.
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