Results 11 to 20 of about 480 (63)

Global structure of sign-changing solutions for discrete Dirichlet problems

open access: yesOpen Mathematics, 2020
Let T>1T\gt 1 be an integer, T≔[1,T]Z={1,2,…,T},Tˆ≔{0,1,…,T+1}{\mathbb{T}}:= {{[}1,T]}_{{\mathbb{Z}}}=\{1,2,\ldots ,T\},\hspace{.0em}\hat{{\mathbb{T}}}:= \{0,1,\ldots ,T+1\}.
Wei Liping, Ma Ruyun
doaj   +1 more source

Perturbation of eigenvalues of matrix pencils and optimal assignment problem [PDF]

open access: yes, 2004
We consider a matrix pencil whose coefficients depend on a positive parameter $\epsilon$, and have asymptotic equivalents of the form $a\epsilon^A$ when $\epsilon$ goes to zero, where the leading coefficient $a$ is complex, and the leading exponent $A ...
Baccelli   +13 more
core   +5 more sources

Weak homoclinic solutions of anisotropic discrete nonlinear system with variable exponent

open access: yesNonautonomous Dynamical Systems, 2020
We prove the existence of weak solutions for an anisotropic homoclinic discrete nonlinear system. Suitable Hilbert spaces and norms are constructed. The proof of the main result is based on a minimization method.
Ibrango Idrissa   +3 more
doaj   +1 more source

Eigenfrequencies of generally restrained beams

open access: yesJournal of Applied Mathematics, Volume 2003, Issue 10, Page 503-516, 2003., 2003
We deal with the exact determination of eigenfrequencies of a beam with intermediate elastic constraints and generally restrained ends. It is the purpose of this paper to use the calculus of variations to obtain the equations of motion and the natural boundary conditions, and particularly those at the intermediate constraints.
Ricardo Oscar Grossi   +1 more
wiley   +1 more source

On a problem in eigenvalue perturbation theory [PDF]

open access: yes, 2015
We consider additive perturbations of the type $K_t=K_0+tW$, $t\in [0,1]$, where $K_0$ and $W$ are self-adjoint operators in a separable Hilbert space $\mathcal{H}$ and $W$ is bounded.
Gesztesy, Fritz   +2 more
core   +1 more source

Spectral analysis in thin tubes with axial heterogeneities

open access: yes, 2015
In this paper, we present the 3D-1D asymptotic analysis of the Dirichlet spectral problem associated with an elliptic operator with axial periodic heterogeneities.
Rita Ferreira   +2 more
semanticscholar   +1 more source

A minimax principle for eigenvalues in spectral gaps: Dirac operators with Coulomb potentials.

open access: yesDocumenta Mathematica, 1999
We prove the minimax principle for eigenvalues in spectral gaps introduced in [5] based on an alternative set of hypotheses. In the case of the Dirac operator these new assumptions allow for potentials with Coulomb singularites.
M. Griesemer, R. Lewis, H. Siedentop
semanticscholar   +1 more source

Spectrum perturbations of compact operators in a Banach space

open access: yesOpen Mathematics, 2019
For an integer p ≥ 1, let Γp be an approximative quasi-normed ideal of compact operators in a Banach space with a quasi-norm NΓp(.) and the ...
Gil’ Michael
doaj   +1 more source

PT Symmetric Schr\"odinger Operators: Reality of the Perturbed Eigenvalues [PDF]

open access: yes, 2010
We prove the reality of the perturbed eigenvalues of some PT symmetric Hamiltonians of physical interest by means of stability methods. In particular we study 2-dimensional generalized harmonic oscillators with polynomial perturbation and the one ...
Caliceti, Emanuela   +2 more
core   +5 more sources

The Diagonalizable Nonnegative Inverse Eigenvalue Problem

open access: yesSpecial Matrices, 2018
In this articlewe provide some lists of real numberswhich can be realized as the spectra of nonnegative diagonalizable matrices but which are not the spectra of nonnegative symmetric matrices.
Cronin Anthony G, Laffey Thomas J.
doaj   +1 more source

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