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We consider a minimal equicontinuous action of a finitely generated group $G$ on a Cantor set $X$ with invariant probability measure $\mu$, and stabilizers of points for such an action. We give sufficient conditions under which there exists…

Dynamical Systems · Mathematics 2020-08-17 Maik Gröger , Olga Lukina

The notion of "super convex spaces" generalizes the idea of convex spaces by replacing finite affine sums with countable affine sums. Using this notion permits a very elegant approach for analysis of the Giry monad on standard measurable…

Category Theory · Mathematics 2022-08-09 Kirk Sturtz

The properties of the space $\A$ of regular connections as a subset of the space $\Ab$ of generalized connections in the Ashtekar framework are studied. For every choice of compact structure group and smoothness category for the paths it is…

Mathematical Physics · Physics 2009-11-07 Christian Fleischhack

We consider one dimensional maps with several neutral fixed points that do not admit any physical measures. We show that there is simplex of measures so that every measure in this simplex has a basin which has full Hausdorff dimension.

Dynamical Systems · Mathematics 2025-09-12 Douglas Coates , Katrin Gelfert

This paper presents a constructive proof of the existence of a regular non-atomic strictly-positive measure on any second-countable non-atomic locally compact Hausdorff space. This construction involves a sequence of finitely-additive set…

Functional Analysis · Mathematics 2020-02-21 Jason Bentley

We explore a notion of pseudofinite dimension, introduced by Hrushovski and Wagner, on an infinite ultraproduct of finite structures. Certain conditions on pseudofinite dimension are identified that guarantee simplicity or supersimplicity…

Logic · Mathematics 2014-10-01 Dario Garcia , Dugald Macpherson , Charles Steinhorn

We study norm convergence and summability of Fourier series in the setting of reduced twisted group $C^*$-algebras of discrete groups. For amenable groups, F{\o}lner nets give the key to Fej\'er summation. We show that Abel-Poisson…

Operator Algebras · Mathematics 2009-07-28 Erik Bedos , Roberto Conti

We provide a necessary and sufficient condition for a simple object in a pivotal k-category to be ambidextrous. In turn, these objects imply the existence of nontrivial trace functions in the category. These functions play an important role…

Representation Theory · Mathematics 2011-12-21 Nathan Geer , Jonathan Kujawa , Bertrand Patureau-Mirand

We investigate Keisler measures in arbitrary theories. Our initial focus is on Borel definability. We show that when working over countable parameter sets in countable theories, Borel definable measures are closed under Morley products and…

Logic · Mathematics 2023-06-28 Gabriel Conant , Kyle Gannon , James Hanson

The existence of a well-behaved dimension of a finite von Neumann algebra (see [19]) has lead to the study of such a dimension of finite Baer *-rings (see [26]) that satisfy certain *-ring axioms (used in [9]). This dimension is closely…

Rings and Algebras · Mathematics 2013-02-05 Lia Vas

We consider finitely generated groups of real-analytic circle diffeomorphisms. We show that if such a group admits an exceptional minimal set (i.e., a minimal invariant Cantor set), then its Lebesgue measure is zero; moreover, there are…

Dynamical Systems · Mathematics 2016-11-03 Bertrand Deroin , Victor Kleptsyn , Andrés Navas

In this article we study for which Cantor sets there exists a gauge-function h, such that the h-Hausdorff-measure is positive and finite. We show that the collection of sets for which this is true is dense in the set of all compact subsets…

Classical Analysis and ODEs · Mathematics 2014-04-10 Carlos Cabrelli , Udayan Darji , Ursula Molter

Let $X$ and $\mathfrak{a}$ be an affine scheme and (respectively) a finite-dimensional associative algebra over an algebraically-closed field $\Bbbk$, both equipped with actions by a linearly-reductive linear algebraic group $G$. We…

Representation Theory · Mathematics 2025-09-03 Alexandru Chirvasitu

In \cite{D3}, Donaldson defines a dynamical system on the space of Fubini-Study metrics on a polarized compact K\"ahler manifold. Sano proved that if there exists a balanced metric for the polarization, then this dynamical system always…

Differential Geometry · Mathematics 2008-12-06 Reza Seyyedali

Ivan Dobrakov has initiated a theory of non-additive set functions defined on a ring of sets intended to be a non-additive generalization of the theory of finite non-negative countably additive measures. These set functions are now known as…

Functional Analysis · Mathematics 2013-09-24 Ondrej Hutník

Motivated by connections between minimal actions, especially T\"oplitz, on Cantor sets, and dimension groups, we find realizations of classes of dimension groups as limits of primitive matrices all of which have equal column sums, or equal…

Functional Analysis · Mathematics 2013-01-15 David Handelman

The set of real numbers which are badly approximable by rationals admits an exhaustion by sets Bad($\epsilon$), whose dimension converges to 1 as $\epsilon$ goes to zero. D. Hensley computed the asymptotic for the dimension up to the first…

Dynamical Systems · Mathematics 2026-03-17 Luca Marchese

We produce a long exact sequence whose terms are unit groups of associative algebras that behave as inner automorphisms of a given tensor. Our sequence generalizes known sequences for associative and non-associative algebras. In a manner…

Rings and Algebras · Mathematics 2020-11-23 Peter A. Brooksbank , Joshua Maglione , James B. Wilson

In the present paper, we study a set that can be treated as a generalised set of subsums for a geometric series. This object was discovered independently in various mathematical aspects. For instance, it is closely related to various…

Probability · Mathematics 2024-10-22 Oleg Makarchuk , Dmytro Karvatskyi

Gowers has elegantly characterized the finite groups $G$ in which $A_1A_2A_3 = G$ for any positive density subsets $A_1,A_2,A_3$. This property, quasi-randomness, holds if and only if G does not admit a nontrivial irreducible representation…

Group Theory · Mathematics 2021-03-23 Mark Sellke