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In a series of papers, we will develop systematically the basic spectral theory of (self-adjoint) boundary value problems for operators of Dirac type. We begin in this paper with the characterization of (self-adjoint) boundary conditions…

Functional Analysis · Mathematics 2007-05-23 Jochen Brüning , Matthias Lesch

This manuscript presents a new extended linear system for integral equation based techniques for solving boundary value problems on locally perturbed geometries. The new extended linear system is similar to a previously presented technique…

Numerical Analysis · Mathematics 2021-03-17 Yabin Zhang , Adrianna Gillman

Existing ultrasound deconvolution approaches unrealistically assume, primarily for computational reasons, that the convolution model relies on a spatially invariant kernel and circulant boundary conditions. We discard both restrictions and…

Signal Processing · Electrical Eng. & Systems 2021-09-21 Mihai I. Florea , Adrian Basarab , Denis Kouamé , Sergiy A. Vorobyov

Blind deconvolution problems are severely ill-posed because neither the underlying signal nor the forward operator are not known exactly. Conventionally, these problems are solved by alternating between estimation of the image and kernel…

Image and Video Processing · Electrical Eng. & Systems 2023-12-06 Yash Sanghvi , Yiheng Chi , Stanley H. Chan

We develop a universally applicable embedded boundary finite difference method, which results in a symmetric positive definite linear system and does not suffer from small cell stiffness. Our discretization is efficient for the wave, heat…

Numerical Analysis · Mathematics 2022-04-14 Zhichao Peng , Daniel Appelö , Shuang Liu

We present a construction of harmonic functions on bounded domains for the spectral fractional Laplacian operator and we classify them in terms of their divergent profile at the boundary. This is used to establish and solve boundary value…

Analysis of PDEs · Mathematics 2015-09-22 Nicola Abatangelo , Louis Dupaigne

A variety of boundary value problems in linear transport theory are expressed as a diffusion equation of the two-way, or forward-backward, type. In such problems boundary data are specified only on part of the boundary, which introduces…

Mathematical Physics · Physics 2019-02-18 Caleb G. Wagner , Richard Beals

In this paper we discuss a new approach to the quasinormal-mode problem in general relativity. By combining a characteristic formulation of the perturbation equations with the integration of a suitable phase-function for a complex valued…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Lars Samuelsson , Nils Andersson , Asimina Maniopoulou

Kernel density estimation on a finite interval poses an outstanding challenge because of the well-recognized bias at the boundaries of the interval. Motivated by an application in cancer research, we consider a boundary constraint linking…

Statistics Theory · Mathematics 2020-12-01 Matthew J. Colbrook , Zdravko I. Botev , Karsten Kuritz , Shev MacNamara

The recent development of spectral method has been praised for its high-order convergence in simulating complex physical problems. The combination of embedded boundary method and spectral method becomes a mainstream way to tackle…

Numerical Analysis · Mathematics 2018-03-08 Po-Yi Wu , Cheng-Hong Robert Kao , Tony Wen-Hann Sheu

A finite difference method is constructed to solve singularly perturbed convection-diffusion problems posed on smooth domains. Constraints are imposed on the data so that only regular exponential boundary layers appear in the solution. A…

Numerical Analysis · Mathematics 2021-12-23 Alan F. Hegarty , Eugene O'Riordan

We obtain two-sided heat kernel estimates for Riemannian manifolds with ends with mixed boundary condition, provided that the heat kernels for the ends are well understood. These results extend previous results of Grigor'yan and…

Differential Geometry · Mathematics 2025-01-15 Emily Dautenhahn , Laurent Saloff-Coste

A review is presented of some recent progress in spectral geometry on manifolds with boundary: local boundary-value problems where the boundary operator includes the effect of tangential derivatives; application of conformal variations and…

High Energy Physics - Theory · Physics 2007-05-23 Giampiero Esposito

We propose a new approach to the spectral theory of perturbed linear operators , in the case of a simple isolated eigenvalue. We obtain two kind of results: ''radius bounds'' which ensure perturbation theory applies for perturbations up to…

Spectral Theory · Mathematics 2025-04-08 Benoît Kloeckner

Conditionally positive definite (CPD) kernels are defined with respect to a function class $\mathcal{F}$. It is well known that such a kernel $K$ is associated with its native space (defined analogously to an RKHS), which in turn gives rise…

Machine Learning · Computer Science 2026-05-26 Rustem Takhanov , Zhenisbek Assylbekov

The goal of the present work is to solve a linear dispersive equation with variable coefficient advection on an unbounded domain. In this setting, transparent boundary conditions are vital to allow waves to leave (or even re-enter) the,…

Numerical Analysis · Mathematics 2021-06-09 Lukas Einkemmer , Alexander Ostermann , Mirko Residori

Recently, the problem of boundary stabilization for unstable linear constant-coefficient coupled reaction-diffusion systems was solved by means of the backstepping method. The extension of this result to systems with advection terms and…

Optimization and Control · Mathematics 2016-03-17 Rafael Vazquez , Miroslav Krstic

In this paper we combine the theory of reproducing kernel Hilbert spaces with the field of collocation methods to solve boundary value problems with special emphasis on reproducing property of kernels. From the reproducing property of…

Numerical Analysis · Mathematics 2019-03-26 Babak Azarnavid , Mahdi Emamjome , Mohammad Nabati , Saeid Abbasbandy

The positive definiteness of real quadratic forms with convolution structures plays an important role in stability analysis for time-stepping schemes for nonlocal operators.In this work, we present a novel analysis tool to handle discrete…

Numerical Analysis · Mathematics 2023-11-23 Hong-lin Liao , Tao Tang , Tao Zhou

A novel method for constructing a Bethe-Salpeter kernel for the meson bound-state problem is described. It produces a closed-form kernel that is symmetry-consistent (discrete and continuous) with the gap equation defined by any admissible…

High Energy Physics - Phenomenology · Physics 2021-08-11 Si-Xue Qin , Craig D. Roberts
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