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Related papers: Some results on nonstationry ideal 2

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In this note we answer the following question of Grinblat: Is it consistent that for some set X, cov(NULL restriction X)=lambda is a weakly inaccessible cardinal (so X not null of course) while cov(meagre) is small, say it is aleph_1.

Logic · Mathematics 2007-05-23 Saharon Shelah

We define a weak iterability notion that is sufficient for a number of arguments concerning $\Sigma_1$-definability at uncountable regular cardinals. In particular we give its exact consistency strength firstly in terms of the second…

Logic · Mathematics 2019-01-18 P. D. Welch

For a strongly inacessible cardinal $\kappa$, we investigate the relationships between the following ideals: - the ideal of meager sets in the ${<}\kappa$-box product topology - the ideal of "null" sets in the sense of [Sh:1004]…

Logic · Mathematics 2023-05-04 Thomas Baumhauer , Martin Goldstern , Saharon Shelah

We show that the existence of a well-known type of ideals on a regular cardinal $\lambda$ implies a compactness property concerning the specialisability of a tree of height $\lambda$ with no cofinal branches. We also use Neeman's method of…

Logic · Mathematics 2023-07-19 Rahman Mohammadpour

A simple \(P_\lambda\)-point on a regular cardinal \(\kappa\) is a uniform ultrafilter on \(\kappa\) with a mod-bounded decreasing generating sequence of length \(\lambda\). We prove that if there is a simple $P_\lambda$-point ultrafilter…

Logic · Mathematics 2025-12-10 Tom Benhamou , Gabriel Goldberg

In this paper we prove a strong nonstructure theorem for kappa (T)-saturated models of a stable theory T with dop.

Logic · Mathematics 2009-09-25 Tapani Hyttinen , Saharon Shelah

We show that the consistency strength of $\kappa$ being $2^\kappa$-square compact is at least weak compact and strictly less than indescribable. This is the first known improvement to the upper bound of strong compactness obtained in 1973…

Logic · Mathematics 2020-04-09 David Buhagiar , Mirna Džamonja

In a countable superstable NDOP theory, the existence of a rigid aleph_epsilon-saturated model implies the existence of 2^lambda rigid aleph_epsilon-saturated models of power lambda for every lambda>2^{aleph_0}.

Logic · Mathematics 2007-05-23 Ziv Shami , Saharon Shelah

We show that Kunen's saturated ideal over $\aleph_1$ is not centered. We also evaluate the extent of saturation of Laver's saturated ideal in terms of $(\kappa,\lambda,<\nu)$-saturation.

Logic · Mathematics 2022-07-26 Kenta Tsukuura

We investigate the cofinality of the strong measure zero ideal for $\kappa$ inaccessible, and show that it is independent of the size of $2^\kappa$.

Logic · Mathematics 2020-12-17 Johannes Philipp Schürz

Given an ordinal delta <= lambda and a cardinal theta <= kappa, an ideal J on P_kappa(lambda) is said to be [delta]^{<theta}-normal if given B_e in J for e in P_theta(delta), the set of all a in P_kappa(lambda) such that a in B_e for some e…

Logic · Mathematics 2007-05-23 Pierre Matet , Cédric Péan , Saharon Shelah

Here we deal with some problems posed by Matet. The first section deals with the existence of stationary subsets of [lambda]^{<kappa} with no unbounded subsets which are not stationary, where, of course, kappa is regular uncountable less or…

Logic · Mathematics 2007-05-23 Saharon Shelah

Motivated by recent results and questions of D. Raghavan and S. Shelah, we present ZFC theorems on the bounding and various almost disjointness numbers, as well as on reaping and dominating families on uncountable, regular cardinals. We…

Logic · Mathematics 2018-03-09 Vera Fischer , Daniel T. Soukup

We prove that the almost sure Lyapunov exponent \lambda(\kappa) of the continuous space Parabolic Anderson Model is bounded above by $c_u \kappa^{1/3}$ as $\kappa\downarrow0$ under mild regularity conditions. This bound of the same order of…

Probability · Mathematics 2013-03-18 Michael Rael

We prove the consistency of: for suitable strongly inaccessible cardinal lambda the dominating number, i.e., the cofinality of ^{lambda}lambda, is strictly bigger than cov_lambda(meagre), i.e. the minimal number of nowhere dense subsets of…

Logic · Mathematics 2020-02-25 Saharon Shelah

We show that generalized eventually narrow sequences on a strongly inaccessible cardinal $\kappa$ are preserved under the Cummings-Shaleh non-linear iterations of the higher Hechler forcing on $\kappa$. Moreover assuming GCH,…

Logic · Mathematics 2020-05-25 Ömer Faruk Bağ , Vera Fischer

It is shown that if T is stable unsuperstable, and aleph_1< lambda =cf(lambda)< 2^{aleph_0}, or 2^{aleph_0} < mu^+< lambda =cf(lambda)< mu^{aleph_0} then T has no universal model in cardinality lambda, and if e.g. aleph_omega < 2^{aleph_0}…

Logic · Mathematics 2016-09-06 Menachem Kojman , Saharon Shelah

In this paper we introduce a tree-like forcing notion extending some properties of the random forcing in the context of the generalised Cantor space and study its associated ideal of null sets and notion of measurability. This issue was…

Logic · Mathematics 2020-04-28 Sy David Friedman , Giorgio Laguzzi

Generalizing Keisler's notion of regularity for ultrafilters, Taylor introduced degrees of regularity for ideals and showed that a countably complete nonregular ideal on $\omega_1$ must be somewhere $\omega_1$-dense. We prove a dichotomy…

Logic · Mathematics 2020-09-04 Monroe Eskew

For $\kappa$ regular and uncountable we define variants of the classical cardinal characteristics modulo the non-stationary ideal.

Logic · Mathematics 2021-05-18 Johannes Philipp Schürz