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Anari, Gharan, and Vinzant proved (complete) log-concavity of the basis generating functions for all matroids. From the viewpoint of combinatorial Hodge theory, it is natural to ask whether these functions are "strictly" log-concave for…

Commutative Algebra · Mathematics 2019-05-31 Takahiro Nagaoka , Akiko Yazawa

We consider a Hamiltonian action of n-dimensional torus, T^n, on a compact symplectic manifold (M,\omega) with d isolated fixed points. For every fixed point p there exists (though not unique) a class a_p in H^*_{T}(M; Q) such that the…

Symplectic Geometry · Mathematics 2013-01-23 Milena Pabiniak

We consider the problem of sampling from a $d$-dimensional log-concave distribution $\pi(\theta) \propto \exp(-f(\theta))$ for $L$-Lipschitz $f$, constrained to a convex body with an efficiently computable self-concordant barrier function,…

Data Structures and Algorithms · Computer Science 2024-11-14 Yuzhou Gu , Nikki Lijing Kuang , Yi-An Ma , Zhao Song , Lichen Zhang

We completely characterize isoperimetric regions in R^n with density e^h, where h is convex, smooth, and radially symmetric. In particular, balls around the origin constitute isoperimetric regions of any given volume, proving the Log-Convex…

Differential Geometry · Mathematics 2015-03-17 Gregory R. Chambers

We prove a sharp moment inequality for a log-concave or a log-convex function, on Gaussian random vectors. As an application we take a stability result for the classical logarithmic Sobolev inequality of L. Gross in the case where the…

Probability · Mathematics 2016-10-17 Nikos Dafnis , Grigoris Paouris

We show that the Poincar\'e constant of a log-concave measure in Euclidean space is monotone increasing along the heat flow. In fact, the entire spectrum of the associated Laplace operator is monotone decreasing. Two proofs of these results…

Metric Geometry · Mathematics 2021-09-01 Bo'az Klartag , Eli Putterman

We show that proper Lie groupoids are locally linearizable. As a consequence, the orbit space of a proper Lie groupoid is a smooth orbispace (a Hausdorff space which locally looks like the quotient of a vector space by a linear compact Lie…

Symplectic Geometry · Mathematics 2007-05-23 Nguyen Tien Zung

Let $(M,\omega)$ be a $2n$-dimensional smooth compact symplectic manifold equipped with a Hamiltonian circle action with only isolated fixed points and let $\mu : M \rightarrow \R$ be a corresponding moment map. Let $\Lambda_{2k}$ be the…

Symplectic Geometry · Mathematics 2013-12-24 Yunhyung Cho , Min Kyu Kim

A complexity-one space is a compact symplectic manifold $(M, \omega)$ endowed with an effective Hamiltonian action of a torus $T$ of dimension $\frac{1}{2}\dim(M)-1$. In this note we prove that for a certain class of complexity-one spaces…

Algebraic Topology · Mathematics 2020-01-31 Isabelle Charton

We study the fixed point for a non-linear transformation in the set of Hausdorff moment sequences, defined by the formula: $T((a_n))_n=1/(a_0+... +a_n)$. We determine the corresponding measure $\mu$, which has an increasing and convex…

Classical Analysis and ODEs · Mathematics 2016-08-14 Christian Berg , Antonio J. Durán

We prove Lieb type convexity and concavity results for trace functionals associated with positive operator monotone (decreasing) functions and certain monotone concave functions. This gives a partial generalization of Hiai's recent work on…

Functional Analysis · Mathematics 2021-06-18 Hans Henrich Neumann , Makoto Yamashita

A Theorem due to Guillemin and Sternberg about geometric quantization of Hamiltonian actions of compact Lie groups $G$ on compact Kaehler manifolds says that the dimension of the $G$-invariant subspace is equal to the Riemann-Roch number of…

alg-geom · Mathematics 2008-02-03 Eckhard Meinrenken

Given a compact symplectic manifold M with the Hamiltonian action of a torus T, let zero be a regular value of the moment map, and M_0 the symplectic reduction at zero. Denote by \kappa_0 the Kirwan map H^*_T(M)-> H^*(M_0). For an…

Symplectic Geometry · Mathematics 2007-05-23 Lisa Jeffrey , Mikhail Kogan

Eigenvalues inequalities involving (log) convex/concav functions and Hermitian matrices, positive unital maps are considered. Simple proofs of Bhatia-Kittaneh inequality and Naimark dilation theorem are given.

Operator Algebras · Mathematics 2007-05-23 Jaspal Singh Aujla Jean-Christophe Bourin

In our previous paper on this topic, we introduced the notion of k-Hessian measure associated with a continuous k-convex function in a domain \Om in Euclidean n-space, k=1,...,n, and proved a weak continuity result with respect to local…

Functional Analysis · Mathematics 2007-05-23 Neil S. Trudinger , Xu-Jia Wang

The property of measure concentration is that an arbitrary 1-Lipschitz function $f:X\to \mathbb{R}$ on an mm-space $X$ is almost close to a constant function. In this paper, we prove that if such a concentration phenomenon arise, then any…

Metric Geometry · Mathematics 2007-05-23 Kei Funano

This is a brief review of the main results of our paper arXiv:1101.1759 that contains a complete global treatment of the compactified trigonometric Ruijsenaars-Schneider system by quasi-Hamiltonian reduction. Confirming previous conjectures…

Mathematical Physics · Physics 2013-08-30 L. Feher , C. Klimcik

We propose a conjecture on the density of arithmetic points in the deformation space of representations of the \'etale fundamental group in positive characteristic. This? conjecture has applications to \'etale cohomology theory, for example…

Algebraic Geometry · Mathematics 2025-04-16 Hélène Esnault , Moritz Kerz

A theorem of Tietze and Nakamija, from 1928, asserts that if a subset X of R^n is closed, connected, and locally convex, then it is convex. We give an analogous "local to global convexity" theorem when the inclusion map of X to R^n is…

Combinatorics · Mathematics 2009-11-19 Yael Karshon , Christina Bjorndahl

Spaces of convex and concave functions appear naturally in theory and applications. For example, convex regression and log-concave density estimation are important topics in nonparametric statistics. In stochastic portfolio theory, concave…

Probability · Mathematics 2021-05-25 Peter Baxendale , Ting-Kam Leonard Wong