English
Related papers

Related papers: On two problems of Erdos and Hechler: New methods …

200 papers

This paper exposes a contradiction in the Zermelo-Fraenkel set theory with the axiom of choice (ZFC). While Godel's incompleteness theorems state that a consistent system cannot prove its consistency, they do not eliminate proofs using a…

Logic in Computer Science · Computer Science 2017-01-03 Minseong Kim

We consider weakenings of normality in $\Psi$-spaces and prove that the existence of a MAD family whose $\Psi$-space is almost-normal is independent of \textsf{ZFC}. We also construct a partly-normal not quasi-normal AD family, answering…

General Topology · Mathematics 2021-05-12 César Corral

Let "ex" be the cardinality of the smallest independent family of subsets of omega (independent means that all nontrivial Boolean combinations are infinite) which cannot be extended to a homogeneous independent family. "Homogeneous" means…

Logic · Mathematics 2009-09-25 Martin Goldstern , Saharon Shelah

Four constructions result from a desire to create enhancements to Cantor's infinite real set cardinality. Each continues to keep Cantor's cardinality formulation in place while providing new comparisons of arbitrary infinite sets. To…

General Mathematics · Mathematics 2026-04-24 William Johnston

We show that there are no infinite maximal almost disjoint ("mad") families in Solovay's model, thus solving a long-standing problem posed by A.D.R. Mathias in 1967. We also give a new proof of Mathias' theorem that no analytic infinite…

Logic · Mathematics 2015-03-31 Asger Tornquist

NF set theory using intuitionistic logic is called iNF. We develop the theories of finite sets and their power sets and mappings, finite cardinals and their ordering, cardinal exponentiation, addition, and multiplication. We follow Rosser…

Logic · Mathematics 2025-10-31 Michael Beeson

Cardinal characteristics of the continuum represent the boundaries in size between the countable and the continuum with respect to certain properties of sets. They are often defined as the minimum sizes of families of reals that meet some…

Logic · Mathematics 2025-03-07 Logan McDonald

We introduce the notion of uniform exactness, or uniform amenability at infinity, for discrete groups and prove it for a wide class of groups containing free groups and their limit groups. This shows a novel strong convergence phenomenon…

Group Theory · Mathematics 2026-05-01 Narutaka Ozawa

The problem of classifying tuples of nilpotent matrices over a field under simultaneous conjugation is considered "hopeless". However, for any given matrix order over a finite field, the number of concerned orbits is always finite. This…

Representation Theory · Mathematics 2021-05-06 Jiuzhao Hua

A new general and unified method of summation, which is both regular and consistent, is invented. It is based on the idea concerning a way of integers reordering. The resulting theory includes a number of explicit and closed form summation…

Classical Analysis and ODEs · Mathematics 2011-10-26 Armen Bagdasaryan

We present the first example of a grand unified theory (GUT) with a modular symmetry interpreted as a family symmetry. The theory is based on supersymmetric $SU(5)$ in 6d, where the two extra dimensions are compactified on a…

High Energy Physics - Phenomenology · Physics 2020-02-04 Francisco J. de Anda , Stephen F. King , Elena Perdomo

To determine Euler numbers modulo powers of two seems to be a difficult task. In this paper we achieve this and apply the explicit congruence to give a new proof of a classical result due to M. A. Stern.

Number Theory · Mathematics 2007-05-23 Zhi-Wei Sun

We show that the consistency of $\mathrm{ZF} + \mathrm{AD}_{\mathbb{R}} + ``\Theta$ is measurable$"$ implies the consistency of $\mathrm{ZF} +``\Theta$ is the least strongly regular cardinal and the least measurable cardinal$"$ + $``$all…

Logic · Mathematics 2026-03-11 Rahman Mohammadpour , Otto Rajala , Sebastiano Thei

We give a new proof that there are arbitrarily large indecomposable abelian groups; moreover, the groups constructed are absolutely indecomposable, that is, they remain indecomposable in any generic extension. However, any absolutely rigid…

Logic · Mathematics 2007-05-23 Paul C. Eklof , Saharon Shelah

Mather and Yau showed that an isolated complex hypersurface singularity is completely determined by its moduli algebra. It is shown, for the simple elliptic singularities, how to construct continuous invariants from the moduli algebras and,…

Algebraic Geometry · Mathematics 2007-05-23 Michael G. Eastwood

We prove that for every (infinite cardinal) lambda there is a T_3-space X with clopen basis, 2^mu points where mu = 2^lambda, such that every closed subspace of cardinality <|X| has cardinality < lambda .

Logic · Mathematics 2009-09-25 Saharon Shelah

Whether singularities can form in fluids remains a foundational unanswered question in mathematics. This phenomenon occurs when solutions to governing equations, such as the 3D Euler equations, develop infinite gradients from smooth initial…

We first partly develop a mathematical notion of stable consistency intended to reflect the actual consistency property of human beings. Then we give a generalization of the first and second G\"odel incompleteness theorem to stably…

Logic in Computer Science · Computer Science 2022-08-16 Yasha Savelyev

We prove that for every singular cardinal mu of cofinality omega, the complete Boolean algebra compP_mu(mu) contains as a complete subalgebra an isomorphic copy of the collapse algebra Comp Col(omega_1,mu^{aleph_0}). Consequently, adding a…

Logic · Mathematics 2007-05-23 Menachem Kojman , Saharon Shelah

The cardinal direction calculus (CDC) proposed by Goyal and Egenhofer is a very expressive qualitative calculus for directional information of extended objects. Early work has shown that consistency checking of complete networks of basic…

Artificial Intelligence · Computer Science 2010-11-05 Weiming Liu , Sanjiang Li
‹ Prev 1 8 9 10 Next ›