1Department of Mathematics University of Nebraska at Omaha Omaha, NE 68182-0243, U.S.A. 2Institute of Mathematics The Hebrew University of Jerusalem 91904 Jerusalem, Israel and Department of Mathematics Rutgers University New Brunswick, NJ 08854, U.S.A.
Colloquium Mathematicum, Tome 134 (2014) no. 2, pp. 211-225
We show the consistency of “there is a nice $\sigma $-ideal ${\mathcal I}$ on the reals with ${\rm add}({\mathcal I})=\aleph _1$ which cannot be represented as the union of a strictly increasing sequence of length $\omega _1$ of $\sigma $-subideals”. This answers [Borodulin-Nadzieja and Głąb, Math. Logic Quart. 57 (2011), 582–590, Problem 6.2(ii)].
Keywords:
consistency there nice sigma ideal mathcal reals mathcal aleph which cannot represented union strictly increasing sequence length omega sigma subideals answers borodulin nadzieja math logic quart problem
Affiliations des auteurs :
Andrzej Rosłanowski 
1
;
Saharon Shelah 
2
1
Department of Mathematics University of Nebraska at Omaha Omaha, NE 68182-0243, U.S.A.
2
Institute of Mathematics The Hebrew University of Jerusalem 91904 Jerusalem, Israel and Department of Mathematics Rutgers University New Brunswick, NJ 08854, U.S.A.
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author = {Andrzej Ros{\l}anowski and Saharon Shelah},
title = {Around ${\rm cofin}$},
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