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arXiv · 1004.1879

The relation of rapid ultrafilters and Q-points to van der Waerden ideal

Jana Flašková
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Abstract

We point out one of the differences between rapid ultrafilters and Q-points: Rapid ultrafilters may have empty intersection with van der Waerden ideal, whereas every Q-point has a non-empty intersection with van der Waerden ideal. Assuming Martin's axiom for countable posets we also construct a W-ultrafilter which is not a Q-point.

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BibTeXRIS

Jana Flašková. 2010-05-29. The relation of rapid ultrafilters and Q-points to van der Waerden ideal. https://arxiv.org/abs/1004.1879

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