In this paper, we prove that a Cauchy symmetric space has a point-countable cs-network if and only if it is a 1-sequence-covering compact-covering quotient π, s-image of a metric space; if and only if it is a sequence-covering quotient π, s-image of a metric space.
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Let Δ be the sets of all topological spaces satisfying the following conditions. (1) Each compact subset of X is metrizable; (2) There exists an sn-network g-function g on X such that if xn → x and yn Є g(n, xn) for all n Є N, then x is a cluster point of {yn}. In this paper, we prove that if X Є Δ, then each sequentially-quotient boundary-compact map on X is pseudo-sequence-covering; if X Є Δ and X has a point-countable sn-network, then each sequence-covering boundary-compact map on X is 1-sequence-covering. As the applications, we give that each sequentially-quotient boundary-compact map on g-metrizable spaces is pseudo-sequence-covering, and each sequence-covering boundary-compact on g-metrizable spaces is 1-sequence-covering.
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In this paper, we give some properties of rectifiable spaces and their relationship with P-space, metrizable space. These results are used to generalize some results in [2], [9] and [12]. Moreover, we give the conditions for a rectifiable space to be second-countable.
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