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Neural Networks (NNs) can provide major empirical performance improvements for robotic systems, but they also introduce challenges in formally analyzing those systems' safety properties. In particular, this work focuses on estimating the…

Systems and Control · Electrical Eng. & Systems 2021-05-26 Michael Everett , Golnaz Habibi , Jonathan P. How

We investigate the performance of a deterministic GREEDY algorithm for the problem of maximizing functions under a partition matroid constraint. We consider non-monotone submodular functions and monotone subadditive functions. Even though…

Discrete Mathematics · Computer Science 2019-02-22 Tobias Friedrich , Andreas Göbel , Frank Neumann , Francesco Quinzan , Ralf Rothenberger

This paper establishes new upper bounds for the $A$-numerical radius of operator matrices in semi-Hilbertian spaces by leveraging the $A$-Buzano inequality and developing refined techniques for operator matrices. We present several sharp…

Functional Analysis · Mathematics 2025-07-08 M. H. M. Rashid

In this paper, we derive sharp bounds on the semigroup of the linearized incompressible Navier-Stokes equations near a stationary shear layer in the half plane and in the half space ($\mathbb{R}_+^2$ or $\mathbb{R}_+^3$), with Dirichlet…

Analysis of PDEs · Mathematics 2019-12-25 Emmanuel Grenier , Toan T. Nguyen

In this paper we obtain sharp Lieb-Thirring inequalities for a Schr\"odinger operator on semi-axis with a matrix potential and show how they can be used to other related problems. Among them are spectral inequalities on star graphs and…

Mathematical Physics · Physics 2019-12-10 Pavel Exner , Ari Laptev , Muhammad Usman

This paper studies an optimization problem on the sum of traces of matrix quadratic forms on $m$ orthogonal matrices, which can be considered as a generalization of the synchronization of rotations. While the problem is nonconvex, the paper…

Optimization and Control · Mathematics 2019-11-21 Teng Zhang

The constrained orthogonal Procrustes problem is the least-squares problem that calls for a rotation matrix that optimally aligns two corresponding sets of points in d-dimensional Euclidean space. This problem generalizes to the so-called…

Optimization and Control · Mathematics 2019-11-01 Javier Bernal , Jim Lawrence

We investigate the method of conjugate gradients, exploiting inaccurate matrix-vector products, for the solution of convex quadratic optimization problems. Theoretical performance bounds are derived, and the necessary quantities occurring…

Numerical Analysis · Computer Science 2020-09-22 S. Gratton , E. Simon , D. Titley-Peloquin , Ph. L. Toint

We establish quantitative upper and lower bounds for Schr\"odinger operators with complex potentials that satisfy some weak form of sparsity. Our first result is a quantitative version of an example, due to S.\ Boegli (Comm. Math. Phys.,…

Spectral Theory · Mathematics 2022-04-20 Jean-Claude Cuenin

In this paper, we present several sharp upper bounds for the numerical radii of the diagonal and off-diagonal parts of the $2\times2$ block operator matrix $\begin{bmatrix}A&B\\ C&D\end{bmatrix}$. Among extensions of some results of…

Functional Analysis · Mathematics 2018-11-01 M. Ghaderi Aghideh , M. S. Moslehian , J. Rooin

Deriving sharp and computable upper bounds of the Lipschitz constant of deep neural networks is crucial to formally guarantee the robustness of neural-network based models. We analyse three existing upper bounds written for the $l^2$ norm.…

Machine Learning · Computer Science 2024-10-29 Moreno Pintore , Bruno Després

We introduce the notion of trace convexity for functions and respectively, for subsets of a compact topological space. This notion generalizes both classical convexity of vector spaces, as well as Choquet convexity for compact metric…

Functional Analysis · Mathematics 2020-04-07 Mohammed Bachir , Aris Daniilidis

We extend to infinite dimensional separable Hilbert spaces the Schur convexity property of eigenvalues of a symmetric matrix with real entries. Our framework includes both the case of linear, selfadjoint, compact operators, and that of…

Analysis of PDEs · Mathematics 2007-05-23 Claude Vallee , Vicentiu Radulescu

We investigate the properties of a class of piecewise-fractional maps arising from the introduction of an invariance under rescaling into convex quadratic maps. The subsequent maps are quasiconvex, and pseudoconvex on specific convex cones;…

Optimization and Control · Mathematics 2025-04-25 Alexandra Zverovich , Matthew Hutchings , Bertrand Gauthier

In this paper, we give upper and lower bounds for the spectral radius of a nonnegative irreducible matrix and characterize the equality cases. These bounds theoretically improve and generalize some known results of Duan et al.[X. Duan, B.…

Combinatorics · Mathematics 2013-10-22 Shu-Yu Cui , Gui-Xian Tian

We establish sharp universal upper bounds on the length of the shortest closed geodesic on a punctured sphere with three or four ends endowed with a complete Riemannian metric of finite area. These sharp curvature-free upper bounds are…

Differential Geometry · Mathematics 2020-09-23 Antonia Jabbour , Stéphane Sabourau

We introduce computational strategies for measuring the ``size'' of the spectrum of bounded self-adjoint operators using various metrics such as the Lebesgue measure, fractal dimensions, the number of connected components (or gaps), and…

Spectral Theory · Mathematics 2024-07-31 Matthew J. Colbrook , Mark Embree , Jake Fillman

It is known that the infimum of the sectional curvatures (on the regular part) of orbit spaces of isometric actions on unit spheres in bounded above by $4$. We show that the infimum is $1$ for "most" actions, and determine the cases in…

Differential Geometry · Mathematics 2018-09-11 Claudio Gorodski

We describe the inequalities on the possible eigenvalues of products of unitary matrices in terms of quantum Schubert calculus. Related problems are the existence of flat connections on the punctured two-sphere with prescribed holonomies,…

alg-geom · Mathematics 2016-08-30 Sharad Agnihotri , Chris Woodward

Schr\"odinger operators with periodic (possibly complex-valued) potentials and discrete periodic operators (possibly with complex-valued entries) are considered, and in both cases the computational spectral problem is investigated: namely,…

Spectral Theory · Mathematics 2021-04-21 Jonathan Ben-Artzi , Marco Marletta , Frank Rösler