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Proceedings of the American Mathematical Society

Published by the American Mathematical Society since 1950, Proceedings of the American Mathematical Society is devoted to shorter research articles in all areas of pure and applied mathematics.

ISSN 1088-6826 (online) ISSN 0002-9939 (print)

The 2020 MCQ for Proceedings of the American Mathematical Society is 0.85.

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by Tamás Mátrai PDF
Proc. Amer. Math. Soc. 137 (2009), 1115-1125 Request permission

Abstract:

We construct a $G_{\delta }$ $\sigma$-ideal $\mathcal {I}$ of compact subsets of $2^{\omega }$ such that $\mathcal {I}$ contains all the singletons but there is no dense $G_{\delta }$ set $D \subseteq 2^{\omega }$ such that $\{K \subseteq D \colon K\textrm { compact}\} \subseteq \mathcal {I}$. This answers a question of A. S. Kechris in the negative.
References
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Additional Information
  • Tamás Mátrai
  • Affiliation: Alfréd Rényi Institute of Mathematics, Hungarian Academy of Sciences, Reáltanoda Street 13-15, H-1053 Budapest, Hungary
  • Address at time of publication: University of Toronto, 40 St. George Street, Toronto, Ontario, M5S 2E4, Canada
  • Email: matrait@renyi.hu
  • Received by editor(s): November 14, 2007
  • Received by editor(s) in revised form: March 9, 2008, and April 14, 2008
  • Published electronically: October 23, 2008
  • Additional Notes: This research was partially supported by the OTKA grants F 43620, K 49786, K 61600 and by the József Öveges Program of the National Office for Research and Technology.
  • Communicated by: Julia Knight
  • © Copyright 2008 American Mathematical Society
    The copyright for this article reverts to public domain 28 years after publication.
  • Journal: Proc. Amer. Math. Soc. 137 (2009), 1115-1125
  • MSC (2000): Primary 03E15; Secondary 54H05, 28A05
  • DOI: https://doi.org/10.1090/S0002-9939-08-09615-9
  • MathSciNet review: 2457453