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Every locally compact regular space, in particular every locally compact Hausdorff space, is a Baire space. [14] [15] That is, the conclusion of the Baire category theorem holds: the interior of every countable union of nowhere dense subsets is empty. A subspace X of a locally compact Hausdorff space Y is locally compact if and only if X is ...
Every topological space X is an open dense subspace of a compact space having at most one point more than X, by the Alexandroff one-point compactification. By the same construction, every locally compact Hausdorff space X is an open dense subspace of a compact Hausdorff space having at most one point more than X.
A Hausdorff, Baire space that is also σ-compact, must be locally compact at at least one point. If G is a topological group and G is locally compact at one point, then G is locally compact everywhere. Therefore, the previous property tells us that if G is a σ-compact, Hausdorff topological group that is also a Baire space, then G is
Every quotient of a locally compact group is locally compact. The product of a family of locally compact groups is locally compact if and only if all but a finite number of factors are actually compact. Topological groups are always completely regular as topological spaces. Locally compact groups have the stronger property of being normal.
In mathematics, in general topology, compactification is the process or result of making a topological space into a compact space. [1] A compact space is a space in which every open cover of the space contains a finite subcover. The methods of compactification are various, but each is a way of controlling points from "going off to infinity" by ...
The theory of Radon measures has most of the good properties of the usual theory for locally compact spaces, but applies to all Hausdorff topological spaces. The idea of the definition of a Radon measure is to find some properties that characterize the measures on locally compact spaces corresponding to positive functionals, and use these ...
The first definition is usually taken for locally compact, countably compact, metrizable, separable, countable; the second for locally connected. [15] Locally closed subset A subset of a topological space that is the intersection of an open and a closed subset. Equivalently, it is a relatively open subset of its closure. Locally compact
Every locally compact sober space is a Baire space. [24] Every finite topological space is a Baire space (because a finite space has only finitely many open sets and the intersection of two open dense sets is an open dense set [25]). A topological vector space is a Baire space if and only if it is nonmeagre, [26] which happens if and only if ...