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We show if a metric measure space admits a differentiable structure then porous sets have measure zero and hence the measure is pointwise doubling. We then give a construction to show if we only require an approximate differentiable…

Metric Geometry · Mathematics 2014-02-11 David Bate , Gareth Speight

We consider impulsive dynamical systems defined on compact metric spaces and their respective impulsive semiflows. We establish sufficient conditions for the existence of probability measures which are invariant by such impulsive semiflows.…

Dynamical Systems · Mathematics 2015-06-19 Jose F. Alves , Maria Carvalho

Given a countable relational language $L$, we consider probability measures on the space of $L$-structures with underlying set $\mathbb{N}$ that are invariant under the logic action. We study the growth rate of the entropy function of such…

Logic · Mathematics 2019-02-20 Nathanael Ackerman , Cameron Freer , Rehana Patel

We argue that it makes sense to talk about ``typical'' properties of lattices, and then show that there is, up to isomorphism, a unique countable lattice L* (the Fraisse limit of the class of finite lattices) that has all ``typical''…

Rings and Algebras · Mathematics 2008-01-09 Martin Goldstern

We provide sufficient conditions for the existence of a trace on the essential $\mathrm{C}^\ast$-algebra of a (not necessarily Hausdorff) \'etale groupoid $G$ which extends an invariant measure $\mu$ on the unit space of $G$. In particular,…

Operator Algebras · Mathematics 2026-03-05 Alistair Miller , Eduardo Scarparo

"An invariant of metric spaces under bornologous equivalences" gives an invariant and "A coarse invariant" extends the invariant to coarse equivalences. In both papers the invariant is defined for a class of metric spaces called sigma…

General Topology · Mathematics 2024-03-20 Michael DeLyser , Brendon LaBuz , Benjamin Wetsell

We use ideas from topological dynamics (amenability), combinatorics (structural Ramsey theory) and model theory (Fra\" {i}ss\' e limits) to study closed amenable subgroups $G$ of the symmetric group $S_\infty$ of a countable set, where…

Logic · Mathematics 2012-05-03 Willem L. Fouche

This paper generalizes the results of [13] and then provides an interesting example. We construct a family of $W$-like maps $\{W_a\}$ with a turning fixed point having slope $s_1$ on one side and $-s_2$ on the other. Each $W_a$ has an…

Dynamical Systems · Mathematics 2013-10-18 Zhenyang Li

We describe a construction process of a relevant measure in any non-empty compact metric space. This probability measure has invariance properties with respect to isometric maps defined on open sets. These properties imply that this measure…

Probability · Mathematics 2014-09-23 Jean-Yves Larrieu

The class of generic structures among those consisting of the measure algebra of a probability space equipped with an automorphism is axiomatizable by positive sentences interpreted using an approximate semantics. The separable generic…

Logic · Mathematics 2007-05-23 Alexander Berenstein , C. Ward Henson

An invariant random subgroup $H \leq G$ is a random closed subgroup whose law is invariant to conjugation by all elements of $G$. When $G$ is locally compact and second countable, we show that for every invariant random subgroup $H \leq G$…

Group Theory · Mathematics 2018-04-24 Ian Biringer , Omer Tamuz

We analyze certain parametrized families of one-dimensional maps with infinitely many critical points from the measure-theoretical point of view. We prove that such families have absolutely continuous invariant probability measures for a…

Dynamical Systems · Mathematics 2010-08-30 Vitor Araujo , Maria Jose Pacifico

We give examples of (i) a simple theory with a formula (with parameters) which does not fork over the empty set but has mu measure 0 for every automorphism invariant Keisler measure mu, and (ii) a definable group G in a simple theory such…

We consider a class of non-locally compact groups on which one may define a left-invariant, finitely additive measure taking values in some finitely generated extension of the field $\mathbb{R}$ of real numbers. In particular, we recover…

Number Theory · Mathematics 2019-02-11 Raven Waller

On metric spaces equipped with doubling measures, we prove that a differentiability theorem holds for Lipschitz functions if and only if the space supports nontrivial (metric) derivations in the sense of Weaver that satisfy an additional…

Metric Geometry · Mathematics 2012-08-15 Jasun Gong

It is shown that any transverse invariant measure of a foliated space can be considered as a measure on the ambient space.

Dynamical Systems · Mathematics 2012-07-12 Carlos Meniño Cotón

While invariant measures are widely employed to analyze physical systems when a direct study of pointwise trajectories is intractable, e.g., due to chaos or noise, they cannot uniquely identify the underlying dynamics. Our first result…

Dynamical Systems · Mathematics 2025-09-30 Jonah Botvinick-Greenhouse , Robert Martin , Yunan Yang

We describe certain sufficient conditions for an infinitely divisible probability measure on a class of connected Lie groups to be embeddable in a continuous one-parameter convolution semigroup of probability measures. (Theorem 1.3). This…

Probability · Mathematics 2020-06-24 S. G. Dani , Yves Guivarc'h , Riddhi Shah

A causal set is a partially ordered set on a countably infinite ground-set such that each element is above finitely many others. A natural extension of a causal set is an enumeration of its elements which respects the order. We bring…

Probability · Mathematics 2011-09-22 Graham Brightwell , Malwina Luczak

The classical de Finetti Theorem classifies the $\mathrm{Sym}(\mathbb N)$-invariant probability measures on $[0,1]^{\mathbb N}$. More precisely it states that those invariant measures are combinations of measures of the form…

Probability · Mathematics 2024-11-05 Colin Jahel , Pierre Perruchaud