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This paper deals with explicit spectral gap estimates for the linearized Boltzmann operator with hard potentials (and hard spheres). We prove that it can be reduced to the Maxwellian case, for which explicit estimates are already known.…

Analysis of PDEs · Mathematics 2016-08-16 Céline Baranger , Clément Mouhot

Let $\Gamma$ be a Schottky subgroup of $\mathrm{SL} (2,\mathbb{Z})$. We establish a uniform and explicit lower bound of the second eigenvalue of the Laplace-Beltrami operator of congruence coverings of the hyperbolic surface $\Gamma…

Spectral Theory · Mathematics 2023-04-20 Irving Calderón , Michael Magee

We investigate when the group $SL_n(\mathcal{O}(X))$ of holomorphic maps from a Stein space $X$ to $SL_n (\C)$ has Kazhdan's property (T) for $n\ge 3$. This provides a new class of examples of non-locally compact groups having Kazhdan's…

Complex Variables · Mathematics 2012-03-01 Björn Ivarsson , Frank Kutzschebauch

In this article we deduce some algebraic properties for the group $\mathrm{Sp}_{2n} (\mathcal{O}(X))$ of holomorphic symplectic matrices on a Stein space $X$: holomorphic factorization, exponential factorization, and Kazhdan's property (T).…

Complex Variables · Mathematics 2022-07-26 Gaofeng Huang , Frank Kutzschebauch , Josua Schott

Decomposition techniques for linear programming are difficult to extend to conic optimization problems with general non-polyhedral convex cones because the conic inequalities introduce an additional nonlinear coupling between the variables.…

Optimization and Control · Mathematics 2013-06-04 Yifan Sun , Martin S. Andersen , Lieven Vandenberghe

Two short seminal papers of Margulis used Kazhdan's property $(T)$ to give, on the one hand, explicit constructions of expander graphs, and to prove, on the other hand, the uniqueness of some invariant means on compact simple Lie groups.…

Group Theory · Mathematics 2018-07-12 Emmanuel Breuillard , Alexander Lubotzky

This paper considers the problem of estimating high dimensional Laplacian constrained precision matrices by minimizing Stein's loss. We obtain a necessary and sufficient condition for existence of this estimator, that consists on checking…

Machine Learning · Statistics 2022-02-24 Eduardo Pavez

An uniform LP duality is an useful property of conic matrix systems. A consistent linear conic optimization problem yields uniform LP duality if for any linear cost function, for which the primal problem has finite optimal value, the…

Optimization and Control · Mathematics 2023-02-21 Kostyukova O. I. , Tchemisova T. , Dudina O. S

We prove resolvent estimates in Schatten spaces for Laplace-Beltrami operators on compact manifolds at the critical exponent. Our proof only uses known bounds for the Hadamard parametrix.

Analysis of PDEs · Mathematics 2025-12-10 Jean-Claude Cuenin

Hidden convexity is a powerful idea in optimization: under the right transformations, nonconvex problems that are seemingly intractable can be solved efficiently using convex optimization. We introduce the notion of a Lagrangian dual…

Optimization and Control · Mathematics 2025-11-07 Venkat Chandrasekaran , Timothy Duff , Jose Israel Rodriguez , Kevin Shu

D. A. Kahzdan first put forth property (T) in relation to the study of discrete subgroups of Lie groups of finite co-volume. Through a combinatorial approach, we define an analogue of property (T) for regular graphs. We then prove the basic…

Combinatorics · Mathematics 2007-05-23 Clara Brasseur , Ryan E. Grady , Stratos Prassidis

Using methods from algebraic graph theory and convex optimization, we study the relationship between local structural features of a network and spectral properties of its Laplacian matrix. In particular, we derive expressions for the…

Optimization and Control · Mathematics 2016-11-17 Victor M. Preciado , Ali Jadbabaie , George C. Verghese

For each countable group $Q$ we produce a short exact sequence $1\to N \to G \to Q\to 1$ where $G$ is f.g. and has a graphical $\frac16$ presentation and $N$ is f.g. and satisfies property $T$. As a consequence we produce a group $N$ with…

Group Theory · Mathematics 2007-05-23 Yann Ollivier , Daniel T. Wise

We study the spectrum of the Finsler--Laplace operator for regular Hilbert geometries, defined by convex sets with $C^2$ boundaries. We show that for an $n$-dimensional geometry, the spectral gap is bounded above by $(n-1)^2/4$, which we…

Differential Geometry · Mathematics 2015-06-23 Thomas Barthelmé , Bruno Colbois , Mickaël Crampon , Patrick Verovic

The aim of this article is to give a simple geometric condition that guarantees the existence of spectral gaps of the discrete Laplacian on periodic graphs. For proving this, we analyse the discrete magnetic Laplacian (DML) on the finite…

Combinatorics · Mathematics 2018-08-08 John Stewart Fabila-Carrasco , Fernando Lledó , Olaf Post

In this article we improve the known Kazhdan constant for $SL_n(Z)$ with respect to the generating set of the elementary matrices. We prove that the Kazhdan constant is bounded from below by $[42\sqrt{n}+860]^{-1}$, which gives the exact…

Group Theory · Mathematics 2007-05-23 Martin Kassabov

This paper concerns spectral clusters of the Neumann Laplacian on compact Riemannian manifolds with strictly geodesically concave boundary. We prove an inequality which controls the $L^p$ norms of spectral clusters.

Analysis of PDEs · Mathematics 2010-11-01 Sinan Ariturk

Motivated by discrete Laplacian differential operators with various accuracy orders in numerical analysis, we introduce new matrices attached to a simple graph that can be considered graph Laplacians with higher accuracy. In particular, we…

Combinatorics · Mathematics 2025-04-09 Mary Yoon

A basic problem in operator theory is to estimate how a small perturbation effects the eigenspaces of a self-adjoint compact operator. In this paper, we prove upper bounds for the subspace distance, taylored for structured random…

Probability · Mathematics 2018-12-18 Moritz Jirak , Martin Wahl

We consider the random iteration of finitely many expanding $\mathcal{C}^{1+\epsilon}$ diffeomorphisms on the real line without a common fixed point. We derive the spectral gap property of the associated transition operator acting on…

Dynamical Systems · Mathematics 2020-03-31 Johannes Jaerisch , Hiroki Sumi