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Combinatorial properties of filters and open covers for sets of real numbers

Published online by Cambridge University Press:  12 March 2014

Claude Laflamme
Affiliation:
Department of Mathematics, The University of Calgary, Calgary, Alberta, Canada T2N-1N4 E-mail: laf@math.ucalgary.ca
Marion Scheepers
Affiliation:
Department of Mathematics, Boise State University, Boise, Idaho 83725, USA E-mail: mscheep@micron.net

Abstract

We analyze combinatorial properties of open covers of sets of real numbers by using filters on the natural numbers. In fact, the goal of this paper is to characterize known properties related to ω-covers of the space in terms of combinatorial properties of filters associated with these ω-covers. As an example, we show that all finite powers of a set of real numbers have the covering property of Menger if, and only if, each filter on ω associated with its countable ω-cover is a P+ filter.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 1999

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