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单词 WeaklyCountablyCompact
释义

weakly countably compact


A topological spaceMathworldPlanetmath X is said to be weakly countably compact(or limit point compact)if every infinite subset of X has a limit pointPlanetmathPlanetmath.

Every countably compact space is weakly countably compact.The converseMathworldPlanetmath is true in T1 spaces (http://planetmath.org/T1Space).

A metric space is weakly countably compact if and only if it is compactPlanetmathPlanetmath.

An easy example of a space Xthat is not weakly countably compactis any infinite set with the discrete topology.A more interesting example is the countable complement topologyon an uncountable set.

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更新时间:2025/5/4 20:34:07