English
Related papers

Related papers: Compactness in singular cardinals revisited

200 papers

Organising the relevant literature and by letting statistical convergence play the main role in the theory of compactness, a variant of compactness called statistical compactness has been achieved. As in case of sequential compactness, one…

General Topology · Mathematics 2022-01-21 Manoranjan Singha , Ujjal Kumar Hom

We discuss how singular can cardinals be in absence of the axiom of choice. We show that, contrasting with known negative consistency results (of Gitik and others), certain positive results are provable. Then we pose some problems.

Logic · Mathematics 2007-09-18 Denis I. Saveliev

We introduce a general version of singular compactness theorem which makes it possible to show that being a $\Sigma$-cotorsion module is a property of the complete theory of the module. As an application of the powerful tools developed…

Representation Theory · Mathematics 2020-03-13 Jan Šaroch , Jan Šťovíček

In 1975 N. Sibony and, independently, M. A. Selby proved that on the complex plane $c$-completeness is equivalent to $c$-finitely compactness. In the paper we give a local version of their results. We also simplify the proofs.

Complex Variables · Mathematics 2018-03-26 Armen Edigarian

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

The consistency of a second-order version of a theorem of Morley on the number of countable models was proved in arXiv:2107.07636 with the aid of large cardinals. We here dispense with them.

Logic · Mathematics 2024-01-22 Franklin D. Tall , Jing Zhang

We give a new, simpler proof of a compactness result in $GSBD^p$, $p>1$, by the same authors, which is also valid in $GBD$ (the case $p=1$), and shows that bounded sequences converge a.e., after removal of a suitable sequence of piecewise…

Functional Analysis · Mathematics 2022-10-11 Antonin Chambolle , Vito Crismale

In this paper we prove that from large cardinals it is consistent that there is a singular strong limit cardinal $\nu$ such that the singular cardinal hypothesis fails at $\nu$ and every collection of fewer than $\mathrm{cf}(\nu)$…

Logic · Mathematics 2023-09-13 Omer Ben-Neria , Yair Hayut , Spencer Unger

A necessary and sufficient compactness criterion in Schauder Spaces is proved.

Functional Analysis · Mathematics 2023-06-27 M. Lanza de Cristoforis

Assuming an abstract comparison principle called the Ultrapower Axiom, which is motivated by the comparison process of inner model theory and generalizes the statement that the Mitchell order is linear on normal ultrafilters, we…

Logic · Mathematics 2018-01-30 Gabriel Goldberg

In this paper, we prove some rigidity theorems for compact Bach-flat $n$-manifold with the positive constant scalar curvature. In particular, our conditions in Theorem 1.4 have the additional properties of being sharp.

Differential Geometry · Mathematics 2017-07-25 Haiping Fu , Jianke Peng

We prove an abstract compactness theorem for a family of generalized Seiberg-Witten equations in dimension three. This result recovers Taubes' compactness theorem for stable flat $\mathbf{P}\mathrm{SL}_2(\mathbf{C})$-connections as well as…

Differential Geometry · Mathematics 2022-02-02 Thomas Walpuski , Boyu Zhang

We prove the consistency of a singular cardinal $\lambda$ with small value of the ultrafilter number $u_\lambda$, and arbitrarily large value of $2^\lambda$.

Logic · Mathematics 2012-11-09 Shimon Garti , Saharon Shelah

The work presents the second part of the second edition of its previous one published in 2000 under the same title, containing the proof (in ZF) of the inaccessible cardinals nonexistence, which is enriched and improved now. This part…

Logic · Mathematics 2011-10-13 A. Kiselev

We extend a theorem by Juh\'asz and Szentmikl\'ossy to notions related to pseudocompactness. We also allow the case when one of the cardinals under consideration is singular. We give an application to the study of decomposable ultrafilters:…

General Topology · Mathematics 2013-05-23 Paolo Lipparini

An improvement of the author's result, proved in 1961, concerning necessary and sufficient conditions for the compactness of an imbedding operator is given.

Functional Analysis · Mathematics 2007-05-23 A. G. Ramm

In order to have a better description of homogenization for parabolic partial differential equations with periodic coefficients, we define the notion of parametric two-scale convergence. A compactness theorem is proved to justify this…

Analysis of PDEs · Mathematics 2007-05-23 Hee Chul Pak

Uhlenbeck's compactness theorem can be used to analyze sequences of connections with anti-self dual curvature on principal SU(2) bundles over oriented 4-dimensional manifolds. The theorems in this paper give an extension of Uhlenbeck's…

Differential Geometry · Mathematics 2020-09-01 Clifford Henry Taubes

We prove a compactness result in GBD which also provides a new proof of the compactness theorem in GSBD, due to Chambolle and Crismale [5, Theorem 1.1]. Our proof is based on a Fr\'echet-Kolmogorov compactness criterion and does not rely on…

Analysis of PDEs · Mathematics 2021-11-22 Stefano Almi , Emanuele Tasso

Generalizing some earlier techniques due to the second author, we show that Menas' theorem which states that the least cardinal kappa which is a measurable limit of supercompact or strongly compact cardinals is strongly compact but not…

Logic · Mathematics 2016-09-06 Arthur Apter , Saharon Shelah