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We obtain a compactness result for $\Gamma$-convergence of integral functionals defined on $\mathcal{A}$-free vector fields. This is used to study homogenization problems for these functionals without periodicity assumptions. More…

Analysis of PDEs · Mathematics 2026-03-10 Gianni Dal Maso , Rita Ferreira , Irene Fonseca

We show that every limit point of a Zariski dense discrete subgroup $\Gamma$ of the isometry group of a symmetric space of noncompact type is conical if and only if $\Gamma$ is convex cocompact.

Geometric Topology · Mathematics 2018-05-01 Sungwoon Kim

The free closed semialgebraic set $D_f$ determined by a hermitian noncommutative polynomial $f$ is the closure of the connected component of $\{(X,X^*)\mid f(X,X^*)>0\}$ containing the origin. When $L$ is a hermitian monic linear pencil,…

Functional Analysis · Mathematics 2021-06-03 J. W. Helton , I. Klep , S. McCullough , J. Volčič

Let G be any locally compact, unimodular, metrizable group. The main result of this paper, roughly stated, is that if F<G is any finitely generated free group and \Gamma < G any lattice, then up to a small perturbation and passing to a…

Group Theory · Mathematics 2014-11-11 Lewis Bowen

$\Gamma$-convergence techniques are used to give a characterization of the behavior of a family of heterogeneous multiple scale integral functionals. Periodicity, standard growth conditions and nonconvexity are assumed whereas a stronger…

Analysis of PDEs · Mathematics 2007-05-23 Jean-Francois Babadjian , Margarida Baia

We study homogenization by Gamma-convergence of periodic multiple integrals of the calculus of variations when the integrand can take infinite values outside of a convex set of matrices.

Classical Analysis and ODEs · Mathematics 2011-01-06 Omar Anza Hafsa , Jean-Philippe Mandallena

Hilbert's Nullstellensatz is one of the most fundamental correspondences between algebra and geometry, and has inspired a plethora of noncommutative analogs. In last two decades, there has been an increased interest in understanding…

Rings and Algebras · Mathematics 2024-03-12 Jurij Volčič

Let $SM_n(\mathbb{R})^g$ denote $g$-tuples of $n \times n$ real symmetric matrices and set $SM(\mathbb{R})^g = \cup_n SM_n(\mathbb{R})^g$. A free quadrilateral is the collection of tuples $X \in SM(\mathbb{R})^2$ which have positive…

Functional Analysis · Mathematics 2022-02-24 Eric Evert

Let $G = V, E$ be a simple connected undirected graph. A set $X \subseteq V$ is \emph{geodesically convex} if for any pair of vertices $x, y \in X$, all vertices on all shortest paths in $G$ from $x$ to $y$ are contained in $X$. A set $H…

Discrete Mathematics · Computer Science 2026-04-20 Niranjan Nair

This article resides in the realm of the noncommutative (free) analog of real algebraic geometry - the study of polynomial inequalities and equations over the real numbers - with a focus on matrix convex sets $C$ and their projections $\hat…

Functional Analysis · Mathematics 2018-04-27 J. William Helton , Igor Klep , Scott McCullough

Let $\Gamma$ be a group which is virtually free of rank at least 2 and let $\mathcal{F}_{td}(\Gamma)$ be the family of totally disconnected, locally compact groups containing $\Gamma$ as a co-compact lattice. We prove that the values of the…

Group Theory · Mathematics 2007-05-23 Udo Baumgartner

Applying the concept of matricial freeness which generalizes freeness in free probability, we have recently studied asymptotic joint distributions of symmetric blocks of Gaussian random matrices (Gaussian Symmetric Block Ensemble). This…

Operator Algebras · Mathematics 2018-05-28 Romuald Lenczewski

In this article, we study the cuts of a totally ordered abelian group $\Gamma$. We begin by recalling some results on ordered sets I and on the associated sets IS(I) and FS(I) of initial and final segments of I. For a totally ordered set I…

Commutative Algebra · Mathematics 2025-12-02 Michel Vaquié

We show that every word hyperbolic, surface-by-(noncyclic) free group Gamma is as rigid as possible: the quasi-isometry group of Gamma equals the abstract commensurator group Comm(Gamma), which in turn contains Gamma as a finite index…

Group Theory · Mathematics 2007-05-23 Benson Farb , Lee Mosher

In this paper we develop a theory of convexity for a free Abelian group M (the lattice of integer points), which we call theory of discrete convexity. We characterize those subsets X of the group M that could be call "convex". One property…

Combinatorics · Mathematics 2007-05-23 V. I. Danilov , G. A. Koshevoy

Let $\Gamma$ be a torsion-free hyperbolic group. We study $\Gamma$--limit groups which, unlike the fundamental case in which $\Gamma$ is free, may not be finitely presentable or geometrically tractable. We define model $\Gamma$--limit…

Group Theory · Mathematics 2017-05-09 Daniel Groves , Henry Wilton

The results on $\Gamma$-limits of sequences of free-discontinuity functionals with bounded cohesive surface terms are extended to the case of vector-valued functions. In this framework, we prove an integral representation result for the…

Analysis of PDEs · Mathematics 2026-01-27 Gianni Dal Maso , Davide Donati

Let $\C(\Gamma)$ be the set of isomorphism classes of the finite groups that are homomorphic images of $\Gamma$. We investigate the extent to which $\C(\Gamma)$ determines $\Gamma$ when $\Gamma$ is a group of geometric interest. If…

Group Theory · Mathematics 2015-01-08 Martin R. Bridson , Marston D. E. Conder , Alan W. Reid

Matrix convexity generalizes convexity to the dimension free setting and has connections to many mathematical and applied pursuits including operator theory, quantum information, noncommutative optimization, and linear control systems. In…

Operator Algebras · Mathematics 2024-05-15 Eric Evert

A group $\Gamma$ has separable cohomology if the profinite completion map $\iota \colon \Gamma \to \widehat{\Gamma}$ induces an isomorphism on cohomology with finite coefficient modules. In this article, cohomological separability is…

Group Theory · Mathematics 2024-06-07 William D. Cohen , Julian Wykowski