Closed mapping theorems on k-spaces with point-countable k-networks
نویسنده
چکیده
We prove some closed mapping theorems on k-spaces with point-countable k-networks. One of them generalizes Lašnev’s theorem. We also construct an example of a Hausdorff space Ur with a countable base that admits a closed map onto metric space which is not compact-covering. Another our result says that a k-space X with a point-countable k-network admitting a closed surjection which is not compact-covering contains a closed copy of Ur.
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تاریخ انتشار 2010