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Related papers: Strongly meager sets can be quite big

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We consider (not self-similar) Cantor sets defined by a sequence of piecewise linear functions. We prove that the dimension of the harmonic measure on such a set is strictly smaller than its Hausdorff dimension. Some Hausdorff measure…

Classical Analysis and ODEs · Mathematics 2013-03-19 Athanasios Batakis , Anna Zdunik

We show that if a separable space X has a meager open subset containing a copy of the Cantor set 2^\omega, then X has $\frak{c}$ types of countable dense subsets. We suggest a generalization of the \lambda-set for non-separable spaces. Let…

General Topology · Mathematics 2014-02-04 Sergey Medvedev

Below, by space we mean a separable metrizable zero-dimensional space. It is studied when the space can be embedded in a Cantor set while maintaining the algebraic structure. Main results of the work: every space is an open retract of a…

General Topology · Mathematics 2023-06-13 Evgenii Reznichenko

Consider $d$ disjoint closed subintervals of the unit interval and consider an orientation preserving expanding map which maps each of these subintervals to the whole unit interval. The set of points where all iterates of this expanding map…

Dynamical Systems · Mathematics 2008-02-03 Feliks Przytycki , Folkert Tangerman

A set of reals A is called perfectly meager if A \cap P is meager in P, for every perfect set P. Marczewski asked if the product of perfectly meager sets is perfectly meager. In the paper it is shown that it is consistent that the answer to…

Logic · Mathematics 2007-05-23 Tomek Bartoszynski

Effective versions of strong measure zero sets are developed for various levels of complexity and computability. It is shown that the sets can be equivalently defined using a generalization of supermartingales called odds supermartingales,…

Logic · Mathematics 2026-01-09 Matthew Rayman

It is proved that the class of separable Rosenthal compacta on the Cantor set having a uniformly bounded dense sequence of continuous functions, is strongly bounded.

Logic · Mathematics 2008-05-15 Pandelis Dodos

We present two constructions of gamma-sets which are large in sense of category.

Logic · Mathematics 2007-05-23 Tomek Bartoszynski , Ireneusz Reclaw

Certain notions of convergence of sequences functions such as pointwise convergence and (uniform) convergence on compact or bounded sets come from suitable topological function spaces; see [1]. Under certain conditions these topologies…

General Mathematics · Mathematics 2025-12-22 Luis David Rivera

Work in the measure algebra of the Lebesgue measure on the Cantor space: for comeager many $[A]$ the set of points $x$ such that the density of $x $ at $A$ is not defined is $\Sigma^{0}_{3}$-complete; for some compact $K$ the set of points…

Logic · Mathematics 2018-08-15 Alessandro Andretta , Riccardo Camerlo , Camillo Costantini

We study some variants of the Erd\H{o}s similarity problem. We pose the question if every measurable subset of the real line with positive measure contains a similar copy of an infinite geometric progression. We construct a compact subset…

Metric Geometry · Mathematics 2023-10-20 Alex Burgin , Samuel Goldberg , Tamás Keleti , Connor MacMahon , Xianzhi Wang

We construct several models where there are no strongly meager sets of size continuum. In particular, there are no such sets in the Laver's model.

Logic · Mathematics 2007-05-23 Tomek Bartoszynski , Saharon Shelah

We study a strengthening of the notion of a universally meager set and its dual counterpart that strengthens the notion of a universally null set. We say that a subset $A$ of a perfect Polish space $X$ is countably perfectly meager…

Logic · Mathematics 2023-04-18 Tomasz Weiss , Piotr Zakrzewski

We show that under natural technical conditions, the sum of a $C^2$ dynamically defined Cantor set with a compact set in most cases (for almost all parameters) has positive Lebesgue measure, provided that the sum of the Hausdorff dimensions…

Dynamical Systems · Mathematics 2016-01-08 David Damanik , Anton Gorodetski

Cantor sets are constructed from iteratively removing sections of intervals. This process yields a cumulative distribution function (CDF), constructed from the invariant measure associated with their iterated function systems. Under…

Classical Analysis and ODEs · Mathematics 2019-12-12 Allison Byars , Evan Camrud , Steven N. Harding , Sarah McCarty , Keith Sullivan , Eric S. Weber

A set $X \subseteq 2^\omega$ with positive measure contains a perfect subset. We study such perfect subsets from the viewpoint of computability and prove that these sets can have weak computational strength. Then we connect the existence of…

Logic · Mathematics 2018-11-05 Chitat Chong , Wei Li , Wei Wang , Yue Yang

Varieties of quantitative algebras are fully described by their free-algebra monads on the category Met of metric spaces. For a longer time it has been an open problem whether the resulting enriched monads are precisely the strongly…

Category Theory · Mathematics 2026-02-06 Jiri Adamek

Similarity metric which is not positive definite, and present a general theorem which provides a large family of similarity metrics which are positive definite.

Functional Analysis · Mathematics 2023-07-21 Daniel Alpay , Liora Mayats-Alpay

A separable metric space X is an H-null set if any uniformly continuous image of X has Hausdorff dimension zero. upper H-null, directed P-null and P-null sets are defined likewise, with other fractal dimensions in place of Hausdorff…

Logic · Mathematics 2012-08-29 Ondrej Zindulka

We resolve the topological version of the Erd\H{o}s Similarity conjecture introduced previously by Gallagher, Lai and Weber. We show that a set is topologically universal on ${\mathbb R}$ if and only if it is of strong measure zero. As a…

Classical Analysis and ODEs · Mathematics 2025-02-19 Yeonwook Jung , Chun-Kit Lai