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We construct subsets of Euclidean space of large Hausdorff dimension and full Minkowski dimension that do not contain nontrivial patterns described by the zero sets of functions. The results are of two types. Given a countable collection of…

Classical Analysis and ODEs · Mathematics 2018-04-18 Robert Fraser , Malabika Pramanik

We show that all finite powers of a Hausdorff space X do not contain uncountable weakly separated subspaces iff there is a c.c.c poset P such that 1_P forces that ``X is a countable union of 0-dimensional subspaces of countable weight.'' We…

Logic · Mathematics 2016-09-06 I. Juhász , Lajos Soukup , Z. Szentmiklóssy

We investigate whether an arbitrary base for a dense-in-itself topological space can be partitioned into two bases. We prove that every base for a T_3 Lindel\"of topology can be partitioned into two bases while there exists a consistent…

General Topology · Mathematics 2014-01-27 Daniel T. Soukup , Lajos Soukup

We show that the ordering of the Hanf number of L_{omega, omega}(wo) (well ordering), L^c_{omega, omega} (quantification on countable sets), L_{omega, omega}(aa) (stationary logic) and second order logic, have no more restraints provable in…

Logic · Mathematics 2013-10-22 Saharon Shelah

For each connected alternating tangle, we provide an infinite family of non-left-orderable L-spaces. This gives further support for Conjecture [3] of Boyer, Gordon, and Watson that is a rational homology 3-sphere is an L-space if and only…

Geometric Topology · Mathematics 2021-11-29 Hamid Abchir , Mohammed Sabak

In the first part of the paper we present and discuss concepts of local and asymptotic hereditary proximity to \ell_1. The second part is devoted to a complete separation of the hereditary local proximity to \ell_1 from the asymptotic one.…

Functional Analysis · Mathematics 2009-08-03 Spiros A. Argyros , Antonis Manoussakis , Anna M. Pelczar

The main purpose of this note is to prove that the product of a cellular Lindelof space with a space of countable spread need not be cellular-Lindelof.

General Topology · Mathematics 2020-12-07 Alan Dow , Robert M. Stephenson

We prove that if ZF is consistent then ZFC+GCH is consistent with the following statement: There is for every k<omega a model of cardinality aleph_1 which is L_{infty,omega_1}-equivalent to exactly k non-isomorphic models of cardinality…

Logic · Mathematics 2007-05-23 Saharon Shelah , Pauli Vaisanen

For a given second order elliptic operation $\mathcal{L}$ in a domain $\Omega\subset{\mathbb{R}}^\mathbf{N}$, $\mathbf{N}\ $, and a compact set $\mathbf{K}\subset\Omega$, order $\mathbf{N}$-$2$-Ahlfors-David regular, we define the space…

Analysis of PDEs · Mathematics 2026-01-07 Grigori Rozenblum , Nikolay Shirokov

We prove the consistency (modulo supercompact) of a negative answer to Arhangelskii's problem (some Hausdorff compact space cannot be partitioned to two sets not containing a closed copy of Cantor discontinuum). In this model we have CH.…

Logic · Mathematics 2007-05-23 Saharon Shelah

We study subspaces of Orlicz spaces $L_M$ spanned by independent copies $f_k$, $k=1,2,\dots$, of a function $f\in L_M$, $\int_0^1 f(t)\,dt=0$. Any such a subspace $H$ is isomorphic to some Orlicz sequence space $\ell_\psi$. In terms of…

Functional Analysis · Mathematics 2024-07-23 Sergey V. Astashkin

In [5], Hjorth proved that for every countable ordinal $\alpha$, there exists a complete $\mathcal{L}_{\omega_1,\omega}$-sentence $\phi_\alpha$ that has models of all cardinalities less than or equal to $\aleph_\alpha$, but no models of…

Logic · Mathematics 2021-09-16 Philipp Lücke , Ioannis Souldatos

We show that there is always a uniformly antisymmetric f:A-> {0,1} if A subset R is countable. We prove that the continuum hypothesis is equivalent to the statement that there is an f:R-> omega with |S_x| <= 1 for every x in R. If the…

Logic · Mathematics 2016-09-06 Peter Komjath , Saharon Shelah

Given a topological property $P$, we say that the space $X$ is $P$-generated if for any subset $A\subset X$ that is not open in $X$ there is a subspace $Y \subset X$ with property $P$ such that $A\cap Y$ is not open in $Y$. (Of course, in…

General Topology · Mathematics 2018-04-10 István Juhász , Lajos Soukup , Zoltán Szentmiklóssy

A space is said to be "almost discretely Lindel\"of" if every discrete subset can be covered by a Lindel\"of subspace. Juh\'asz, Tkachuk and Wilson asked whether every almost discretely Lindel\"of first-countable Hausdorff space has…

General Topology · Mathematics 2017-10-18 Angelo Bella , Santi Spadaro

We will prove that there exists a model of ZFC+``c= omega_2'' in which every M subseteq R of cardinality less than continuum c is meager, and such that for every X subseteq R of cardinality c there exists a continuous function f:R-> R with…

Logic · Mathematics 2016-09-07 Krzysztof Ciesielski , Saharon Shelah

The existence and nonexistence of $\lambda$-harmonic functions in unbounded domains of $\mathbb{H}^n$ are investigated. We prove that if the $(n-1)/2$ Hausdorff measure of the asymptotic boundary of a domain $\Omega$ is zero, then there is…

Analysis of PDEs · Mathematics 2021-07-02 Leonardo Prange Bonorino , Patrícia Kruse Klaser

We establish that the sequences formed by logarithms and by "fractional" powers of integers, as well as the sequence of prime numbers, are non-holonomic, thereby answering three open problems of Gerhold [Electronic Journal of Combinatorics…

Combinatorics · Mathematics 2008-02-28 Philippe Flajolet , Stefan Gerhold , Bruno Salvy

In this work, we revisit the following estimate due to Dahlberg \cite{Dahl}. Let $\textit{\textbf x}_0$ a fixed point in a bounded Lipschitz domain $\Omega$. Then there exists a constant $C > 0$ such that if $u$ is a harmonic function in…

Analysis of PDEs · Mathematics 2026-01-12 Chérif Amrouche , Mohand Moussaoui

In this note, we consider the space $H(\Omega)^{\mathbb N}$ of sequences of holomorphic functions on an open set $\Omega\subset {\mathbb C}$. If $H(\Omega)$ is endowed with its natural topology and $H(\Omega)^{\mathbb N}$ is endowed with…

Complex Variables · Mathematics 2026-03-11 L. Bernal-González , M. C. Calderón-Moreno , J. López-Salazar , J. A. Prado-Bassas