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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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Some consequences of $(V=L)$ in the theory of analytic sets
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by R. W. Hansell PDF
Proc. Amer. Math. Soc. 80 (1980), 311-319 Request permission

Abstract:

Following G. M. Reed’s definition of a Q-set, we define a ${Q_A}$-set to be any non-$\sigma$-discrete topological space with the property that each subset is (relatively) analytic (= Souslin-$\mathcal {F}$ set). Clearly every Q-set is a ${Q_A}$-set. The discrete irrational extension of the space of real numbers is an example of a first countable hereditarily paracompact (Hausdorff) ${Q_A}$-set which is not a Q-set. Theorem. $(V = L)$ Let X be a first countable normal space all of whose subsets are analytic. Then X is $\sigma$-discrete if and only if the product of X with the space of irrational numbers is normal. A new structural property of analytic sets is developed in order to utilize a proof technique due to Reed. Several corollaries are obtained on properties of completely additive-analytic families of sets in general metric spaces.
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Additional Information
  • © Copyright 1980 American Mathematical Society
  • Journal: Proc. Amer. Math. Soc. 80 (1980), 311-319
  • MSC: Primary 54H05; Secondary 03E15, 03E35, 54E35
  • DOI: https://doi.org/10.1090/S0002-9939-1980-0577766-0
  • MathSciNet review: 577766