A class of topologies with $T_1$-complements

B. Anderson

Displaying similar documents to “A class of topologies with $T_{1}$ -complements”

On dense subspaces satisfying stronger separation axioms

Ofelia Teresa Alas, Mihail G. Tkachenko, Vladimir Vladimirovich Tkachuk, Richard Gordon Wilson, Ivan V. Yashchenko (2001)

Czechoslovak Mathematical Journal

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We prove that it is independent of ZFC whether every Hausdorff countable space of weight less than $c$ has a dense regular subspace. Examples are given of countable Hausdorff spaces of weight $c$ which do not have dense Urysohn subspaces. We also construct an example of a countable Urysohn space, which has no dense completely Hausdorff subspace. On the other hand, we establish that every Hausdorff space of $π$ -weight less than $𝔭$ has a dense completely Hausdorff (and hence Urysohn) subspace....

Remarks on dense subspaces

Eva Murtinová (2004)

Czechoslovak Mathematical Journal

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Some constructions of spaces with/without dense subspaces satisfying stronger separation axioms are presented.

Partial discretization of topologies

M. Bonanzinga, F. Cammaroto, M. V. Matveev (2000)

Bollettino dell'Unione Matematica Italiana

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In questo lavoro daremo una construzione che aumenta il numero di sottospazi chiusi e discreti dello spazio e daremo alcune applicazioni di tale construzione.