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The covering number of the strong measure zero ideal can be above almost everything else

The covering number of the strong measure zero ideal can be above almost everything else We show that certain type of tree forcings, including Sacks forcing, increases the covering of the strong measure zero ideal SN\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${{\mathcal {S}}}{{\mathcal {N}}}$$\end{document}. As a consequence, in Sacks model, such covering number is equal to the size of the continuum, which indicates that this covering number is consistently larger than any other classical cardinal invariant of the continuum. Even more, Sacks forcing can be used to force that non(SN)<cov(SN)<cof(SN)\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\mathrm {non}({{\mathcal {S}}}{{\mathcal {N}}})<\mathrm {cov}({{\mathcal {S}}}{{\mathcal {N}}})<\mathrm {cof}({{\mathcal {S}}}{{\mathcal {N}}})$$\end{document}, which is the first consistency result where more than two cardinal invariants associated with SN\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${{\mathcal {S}}}{{\mathcal {N}}}$$\end{document} are pairwise different. Another consequence is that SN⊆s0\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${{\mathcal {S}}}{{\mathcal {N}}}\subseteq s^0$$\end{document} in ZFC where s0\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$s^0$$\end{document} denotes Marczewski’s ideal. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Archive for Mathematical Logic Springer Journals

The covering number of the strong measure zero ideal can be above almost everything else

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References (36)

Publisher
Springer Journals
Copyright
Copyright © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2021
ISSN
0933-5846
eISSN
1432-0665
DOI
10.1007/s00153-021-00808-0
Publisher site
See Article on Publisher Site

Abstract

We show that certain type of tree forcings, including Sacks forcing, increases the covering of the strong measure zero ideal SN\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${{\mathcal {S}}}{{\mathcal {N}}}$$\end{document}. As a consequence, in Sacks model, such covering number is equal to the size of the continuum, which indicates that this covering number is consistently larger than any other classical cardinal invariant of the continuum. Even more, Sacks forcing can be used to force that non(SN)<cov(SN)<cof(SN)\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\mathrm {non}({{\mathcal {S}}}{{\mathcal {N}}})<\mathrm {cov}({{\mathcal {S}}}{{\mathcal {N}}})<\mathrm {cof}({{\mathcal {S}}}{{\mathcal {N}}})$$\end{document}, which is the first consistency result where more than two cardinal invariants associated with SN\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${{\mathcal {S}}}{{\mathcal {N}}}$$\end{document} are pairwise different. Another consequence is that SN⊆s0\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${{\mathcal {S}}}{{\mathcal {N}}}\subseteq s^0$$\end{document} in ZFC where s0\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$s^0$$\end{document} denotes Marczewski’s ideal.

Journal

Archive for Mathematical LogicSpringer Journals

Published: Jul 1, 2022

Keywords: Strong measure zero sets; Cardinal invariants; Sacks model; Yorioka ideals; 03E17; 03E35; 03E40

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