Displaying similar documents to “Strong sequences, binary families and Esenin-Volpin's theorem”

Strong sequences and the weight of regular spaces

Marian Turzański (1992)

Commentationes Mathematicae Universitatis Carolinae

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It will be shown that if in a family of sets there exists a strong sequence of the length ( κ λ ) + then this family contains a subfamily consisting of λ + pairwise disjoint sets. The method of strong sequences will be used for estimating the weight of regular spaces.

Tightness and π-character in centered spaces

Murray Bell (1999)

Colloquium Mathematicae

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We continue an investigation into centered spaces, a generalization of dyadic spaces. The presence of large Cantor cubes in centered spaces is deduced from tightness considerations. It follows that for centered spaces X, πχ(X) = t(X), and if X has uncountable tightness, then t(X) = supκ : 2 κ ⊂ X. The relationships between 9 popular cardinal functions for the class of centered spaces are justified. An example is constructed which shows, unlike the dyadic and polyadic properties, that the...