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We consider Sturm-Liouville problems with a discontinuity in an interior point, which are motivated by the inverse problems for the torsional modes of the Earth. We assume that the potential on the right half-interval and the coefficient in…

Spectral Theory · Mathematics 2019-04-24 Chuan-Fu Yang , Natalia Bondarenko

In this paper we present general-purpose preconditioners for regularized augmented systems arising from optimization problems, and their corresponding normal equations. We discuss positive definite preconditioners, suitable for CG and…

Optimization and Control · Mathematics 2022-04-01 Jacek Gondzio , Spyridon Pougkakiotis , John W. Pearson

We introduce in this document a direct method allowing to solve numerically inverse type problems for linear hyperbolic equations. We first consider the reconstruction of the full solution of the wave equation posed in $\Omega\times (0,T)$…

Optimization and Control · Mathematics 2015-06-11 Nicolae Cindea , Arnaud Munch

The theory of intrinsic volumes of convex cones has recently found striking applications in areas such as convex optimization and compressive sensing. This article provides a self-contained account of the combinatorial theory of intrinsic…

Combinatorics · Mathematics 2017-08-23 Dennis Amelunxen , Martin Lotz

Numerical simulation of fracture contact poromechanics is essential for various applications, including CO2 sequestration, geothermal energy production and underground gas storage. Modeling this problem accurately presents significant…

Numerical Analysis · Mathematics 2025-01-14 Yury Zabegaev , Inga Berre , Eirik Keilegavlen , Kundan Kumar

We follow a stream of the history of positive matrices and positive functionals, as applied to algebraic sums of squares decompositions, with emphasis on the interaction between classical moment problems, function theory of one or several…

Functional Analysis · Mathematics 2007-05-23 John William Helton , Mihai Putinar

In this paper, we generalize the chance optimization problems and introduce constrained volume optimization where enables us to obtain convex formulation for challenging problems in systems and control. We show that many different problems…

Optimization and Control · Mathematics 2017-02-01 Ashkan Jasour , Constantino Lagoa

Kubota's integral formula expresses the intrinsic volumes of a convex body as averages over its projections onto linear subspaces. In this work, we introduce a new class of Kubota-type formulas for mixed area measures adapted to rotations…

Metric Geometry · Mathematics 2026-01-13 Daniel Hug , Fabian Mussnig , Jacopo Ulivelli

We study a nonlinear decomposition of a positive definite matrix into two components: the inverse of another positive definite matrix and a symmetric matrix constrained to lie in a prescribed linear subspace. Equivalently, the inverse…

Optimization and Control · Mathematics 2026-01-27 Yan Dolinsky , Or Zuk

A method to compute guaranteed lower bounds to the eigenvalues of the Maxwell system in two or three space dimensions is proposed as a generalization of the method of Liu and Oishi [SIAM J. Numer. Anal., 51, 2013] for the Laplace operator.…

Numerical Analysis · Mathematics 2022-11-18 Dietmar Gallistl , Vladislav Olkhovskiy

We give a survey of author's results on the inverse hyperbolic problems with time-dependent and time-independent coefficients. We consider the case of hyperbolic equations with Yang-Mills potentials and the case of domains with obstacles.…

Analysis of PDEs · Mathematics 2014-07-22 Gregory Eskin

We describe a modular rewriting system for translating optimization problems written in a domain-specific language to forms compatible with low-level solver interfaces. Translation is facilitated by reductions, which accept a category of…

Optimization and Control · Mathematics 2019-02-28 Akshay Agrawal , Robin Verschueren , Steven Diamond , Stephen Boyd

A class of inverse problems for restoring the right-hand side of a parabolic equation for a large class of positive operators with discrete spectrum is considered. The results on existence and uniqueness of solutions of these problems as…

Analysis of PDEs · Mathematics 2019-11-12 Michael Ruzhansky , Niyaz Tokmagambetov , Berikbol T. Torebek

This paper deals with the fast solution of linear systems associated with the mass matrix, in the context of isogeometric analysis. We propose a preconditioner that is both efficient and easy to implement, based on a diagonal-scaled…

Numerical Analysis · Mathematics 2020-11-30 Gabriele Loli , Giancarlo Sangalli , Mattia Tani

To precondition a large and sparse linear system, two direct methods for approximate factoring of the inverse are devised. The algorithms are fully parallelizable and appear to be more robust than the iterative methods suggested for the…

Numerical Analysis · Mathematics 2012-08-20 Mikko Byckling , Marko Huhtanen

We consider the quantum inverse scattering method for several mixed integrable models based on the rational SU(N) R-matrix with general toroidal boundary conditions. This includes systems whose Hilbert spaces are invariant by the discrete…

Exactly Solvable and Integrable Systems · Physics 2009-11-10 G. A. P. Ribeiro , M. J. Martins

A combination of block-Jacobi and deflation preconditioning is used to solve a high-order discontinuous collocation-based discretization of the Schur complement of the Poisson-Neumann system as arises in the operator splitting of the…

Numerical Analysis · Mathematics 2016-03-23 Sumedh M. Joshi , Greg N. Thomsen , Peter J. Diamessis

Generalized polyhedral convex optimization problems in locally convex Hausdorff topological vector spaces are studied systematically in this paper. We establish solution existence theorems, necessary and sufficient optimality conditions,…

Optimization and Control · Mathematics 2017-10-02 Nguyen Ngoc Luan , Jen-Chih Yao

This work aims to accelerate the convergence of proximal gradient methods used to solve regularized linear inverse problems. This is achieved by designing a polynomial-based preconditioner that targets the eigenvalue spectrum of the normal…

In this note we present a parameterized class of lower triangular matrices. The components of the eigenvectors grow rapidly and will exceed the representational range of any finite number system. The eigenvalues and the eigenvectors are…

Numerical Analysis · Mathematics 2020-05-13 Carl Christian Kjelgaard Mikkelsen