Results 61 to 70 of about 23,326 (218)

New norm equalities and inequalities for operator matrices

Journal of Inequalities and Applications, 2016
We prove new inequalities for general 2 × 2 $2\times2$ operator matrices. These inequalities, which are based on classical convexity inequalities, generalize earlier inequalities for sums of operators. Some other related results are also presented. Also,
Feras Ali Bani-Ahmad, Watheq Bani-Domi
doaj   +1 more source

MINRES-QLP: a Krylov subspace method for indefinite or singular symmetric systems

, 2011
CG, SYMMLQ, and MINRES are Krylov subspace methods for solving symmetric systems of linear equations. When these methods are applied to an incompatible system (that is, a singular symmetric least-squares problem), CG could break down and SYMMLQ's ...
Christopher C. Paige, Hadamard J., Michael A. Saunders, Ren W.-Q., Sou-Cheng T. Choi   +4 more
core   +3 more sources

Formulation and Calibration of CATKE, a One‐Equation Parameterization for Microscale Ocean Mixing

Journal of Advances in Modeling Earth Systems, Volume 17, Issue 4, April 2025.
Abstract We describe CATKE, a parameterization for fluxes associated with small‐scale or “microscale” ocean turbulent mixing on scales between 1 and 100 m. CATKE uses a downgradient formulation that depends on a prognostic turbulent kinetic energy (TKE) variable and a diagnostic mixing length scale that includes a dynamic convective adjustment (CA ...
Gregory LeClaire Wagner, Adeline Hillier, Navid C. Constantinou, Simone Silvestri, Andre Souza, Keaton J. Burns, Chris Hill, Jean‐Michel Campin, John Marshall, Raffaele Ferrari   +9 more
wiley   +1 more source

A Test Matrix for an Inverse Eigenvalue Problem

Journal of Applied Mathematics, 2014
We present a real symmetric tridiagonal matrix of order n whose eigenvalues are {2k}k=0n-1 which also satisfies the additional condition that its leading principle submatrix has a uniformly interlaced spectrum, {2l+1}l=0n-2.
G. M. L. Gladwell, T. H. Jones, N. B. Willms   +2 more
doaj   +1 more source

Generalized Force Method for Point‐To‐Point Ray Tracing in Anisotropic Ionosphere: Implementation and Applications to NeQuick2 and IGRF13 Models

Radio Science, Volume 60, Issue 3, March 2025.
Abstract The generalized force method, previously developed for an isotropic inhomogeneous ionosphere, exploits the knowledge about the character of the extrema of the phase distance—where high ionospheric rays correspond to minima and low rays to saddle points—to systematically find all relevant rays between fixed points, thereby enabling efficient ...
I. A. Nosikov, M. V. Klimenko, A. M. Padokhin, V. V. Nosikova, P. F. Bessarab   +4 more
wiley   +1 more source

The Darboux transformation and the complex Toda lattice [PDF]

, 2008
It is well known that each solution of the Toda lattice can be represented by a tridiagonal matrix J(t). Under certain restrictions, it is possible to obtain some new solution by using the Darboux transformation of J(t) ¡ CI. Our goal is the extension of
Barrios Rolania, Maria Dolores, Branquinho, Amilcar, Foulquié Moreno, E.   +2 more
core   +1 more source

Enumeration of simple random walks and tridiagonal matrices

, 2002
We present some old and new results in the enumeration of random walks in one dimension, mostly developed in works of enumerative combinatorics. The relation between the trace of the $n$-th power of a tridiagonal matrix and the enumeration of weighted ...
Bauer M, Flajolet P, G M Cicuta, Gessel I, Goldsheid I Y, Goulden I P, Jani M, Jonsson T, Klarner D A, Krattenthaler C, L Molinari, Lee D S, M Contedini, Mansour T, Merlini D, Mohanty G, Noh J D, Raykin M, Sachov V, Sinai Ya G, Sinai Ya G, Stanley R P, Stanley R P, Wigner E   +23 more
core   +1 more source

Hurwitz numbers for reflection groups III: Uniform formulae

Journal of the London Mathematical Society, Volume 111, Issue 3, March 2025.
Abstract We give uniform formulae for the number of full reflection factorizations of a parabolic quasi‐Coxeter element in a Weyl group or complex reflection group, generalizing the formula for the genus‐0 Hurwitz numbers. This paper is the culmination of a series of three.
Theo Douvropoulos, Joel Brewster Lewis, Alejandro H. Morales   +2 more
wiley   +1 more source

Affine transformations of a Leonard pair

, 2006
Let $K$ denote a field and let $V$ denote a vector space over $K$ with finite positive dimension. We consider an ordered pair of linear transformations $A : V \to V$ and $A^* : V \to V$ that satisfy (i) and (ii) below: (i) There exists a basis for $V ...
Nomura, Kazumasa, Terwilliger, Paul
core   +2 more sources

Fast Solution of Sylvester‐Structured Systems for Spatial Source Separation of the Cosmic Microwave Background

Numerical Linear Algebra with Applications, Volume 32, Issue 1, February 2025.
ABSTRACT Implementation of many statistical methods for large, multivariate data sets requires one to solve a linear system that, depending on the method, is of the dimension of the number of observations or each individual data vector. This is often the limiting factor in scaling the method with data size and complexity.
Dung Pham, Kirk M. Soodhalter, Simon Wilson   +2 more
wiley   +1 more source