English
Related papers

Related papers: Definable convolution and idempotent Keisler measu…

200 papers

We introduce an algebraic invariant for aperiodic inclusions of probability measure preserving equivalence relations. We use this invariant to prove that every stable orbit equivalence between free pmp actions of direct products of…

Group Theory · Mathematics 2025-07-17 Cyril Houdayer , Sven Raum

We present a systematic study of the regularity phenomena for NIP hypergraphs and connections to the theory of (locally) generically stable measures, providing a model-theoretic hypergraph version of the results from [L. Lov\'asz, B.…

Logic · Mathematics 2021-03-11 Artem Chernikov , Sergei Starchenko

If F is a type-definable family of commensurable subsets, subgroups or sub-vector spaces in a metric structure, then there is an invariant subset, subgroup or sub-vector space commensurable with F. This in particular applies to…

Logic · Mathematics 2020-04-10 Itaï Ben Yaacov , Frank Olaf Wagner

Let F be a non-Archimedean locally compact field with residual characteristic p, let G be an inner form of GL(n,F) for a positive integer n and let R be an algebraically closed field of characteristic different from p. When R has…

Representation Theory · Mathematics 2015-03-23 Alberto Mínguez , Vincent Sécherre

This paper presents analogous results of Hua [7][8] on numbers of representations of quivers over finite fields which respect nilpotent relations under certain assumptions. A closed formula which counts isomorphism classes of absolutely…

Representation Theory · Mathematics 2021-05-06 Bangming Deng , Jiuzhao Hua

We study invariant types in NIP theories. Amongst other things: we prove a definable version of the (p,q)-theorem in theories of small or medium directionality; we construct a canonical retraction from the space of M-invariant types to that…

Logic · Mathematics 2015-11-10 Pierre Simon

In a convolution semigroup over a locally compact group, measurability of the translation by a fixed element implies continuity. In other words, the measurable centre coincides with the topological centre.

Functional Analysis · Mathematics 2012-10-23 Jan Pachl

We prove an analog for integrable measurable cocycles of Pansu's differentiation theorem for Lipschitz maps between Carnot-Carath\'eodory spaces. This yields an alternative, ergodic theoretic proof of Pansu's quasi-isometric rigidity…

Group Theory · Mathematics 2016-08-02 Michael Cantrell

Let $K$ denote a simply connected compact Lie group and let $G=K^{\mathbb C}$, the complexification. It is known that there exists an $LK$ bi-invariant probability measure on a natural hyperfunction completion of the complex loop group…

Mathematical Physics · Physics 2025-12-23 Doug Pickrell

The notion of a proper Ellis semigroup compactification is introduced. Ellis's functional approach shows how to obtain them from totally bounded equiuniformities on a phase space $X$ when the acting group $G$ is with the topology of…

General Topology · Mathematics 2025-07-29 K. L. Kozlov , B. V. Sorin

For a finitely generated group $G$ and collection of subgroups $\mathcal{P}$ we prove that the relative Dehn function of a pair $(G,\mathcal{P})$ is invariant under quasi-isometry of pairs. Along the way we show quasi-isometries of pairs…

Group Theory · Mathematics 2025-01-15 Sam Hughes , Eduardo Martínez-Pedroza , Luis Jorge Sánchez Saldaña

Loop groups G as families of mappings of the complex manifold M into another complex manifold N preserving marked points $s_0\in M$ and $y_0\in N$ are investigated. Quasi-invariant measures $\mu $ on G relative to dense subgroups $G'$ are…

Representation Theory · Mathematics 2007-05-23 S. V. Ludkovsky

We give a new proof of the NIP arithmetic regularity lemma for finite groups (due to the authors and Pillay), which describes the approximate structure of "NIP sets" in finite groups, i.e., subsets whose collection of left translates has…

Combinatorics · Mathematics 2025-09-05 G. Conant , C. Terry

Estimates of densities of convolution semigroups of probability measures are given under specific assumptions on the corresponding L\'evy measure and the L\'evy--Khinchin exponent. The assumptions are satisfied, e.g., by tempered stable…

Probability · Mathematics 2008-04-02 Paweł Sztonyk

We develop topological dynamics for the group of automorphisms of a monster model of any given theory. In particular, we find strong relationships between objects from topological dynamics (such as the generalized Bohr compactification…

Logic · Mathematics 2025-12-10 Krzysztof Krupiński , Anand Pillay , Tomasz Rzepecki

We solve two problems from the paper "On maximal stable quotients of definable groups in NIP theories" by M. Haskel and A. Pillay, which concern maximal stable quotients of groups type-definable in NIP theories. The first result says that…

Logic · Mathematics 2022-05-02 Krzystof Krupiński , Adrián Portillo

In the paper "Einstein metrics on compact simple Lie groups attached to standard triples", the authors introduced the definition of standard triples and proved that every compact simple Lie group $G$ attached to a standard triple $(G,K,H)$…

Differential Geometry · Mathematics 2017-01-09 Huibin Chen , Zhiqi Chen

In this note we study sets of NIP formulas in some theories of fields and valued fields, with a special focus on the sets of quantifier-free and existential formulas. First, we give a new proof of the fact that Separably Closed Valued…

Logic · Mathematics 2026-02-04 Paulo Andrés Soto Moreno

We prove that any type in an NIP theory can be decomposed into a stable part (a generically stable partial type) and a distal-like quotient.

Logic · Mathematics 2017-08-03 Pierre Simon

We prove that the isomorphism problem is decidable for generalized Baumslag-Solitar (GBS) groups with one quasi-conjugacy class and full support gaps. In order to do so we introduce a family of invariants that fully characterize the…

Group Theory · Mathematics 2025-08-05 Dario Ascari , Montserrat Casals-Ruiz , Ilya Kazachkov