Zobrazeno 1 - 10
of 57
pro vyhledávání: '"Naboko, Sergey"'
The spectral and scattering properties of non-selfadjoint problems pose a mathematical challenge. Apart from exceptional cases, the well-developed methods used to examine the spectrum of selfadjoint problems are not applicable. One of the tools to at
Externí odkaz:
http://arxiv.org/abs/2212.00708
Motivated by recent results concerning the asymptotic behaviour of differential operators with highly contrasting coefficients, which have involved effective descriptions involving generalised resolvents, we construct the functional model for a typic
Externí odkaz:
http://arxiv.org/abs/2111.05387
Let $L^2(D)$ be the space of measurable square-summable functions on the unit disk. Let $L^2_a(D)$ be the Bergman space, i.e., the (closed) subspace of analytic functions in $L^2(D)$. $P_+$ stays for the orthogonal projection going from $L^2(D)$ to $
Externí odkaz:
http://arxiv.org/abs/2006.02586
This paper provides decay bounds for Green matrices and generalized eigenvectors of block Jacobi operators when the real part of the spectral parameter lies in a bounded gap of the operator's essential spectrum. The case of the spectral parameter bei
Externí odkaz:
http://arxiv.org/abs/1905.04688
Publikováno v:
Journal of Difference Equations and Applications Volume 24, 2018 - Issue 8 (2018)
We consider the problem of embedding eigenvalues into the essential spectrum of periodic Jacobi operators, using an oscillating, decreasing potential. To do this we employ a geometric method, previously used to embed eigenvalues into the essential sp
Externí odkaz:
http://arxiv.org/abs/1805.03701
Publikováno v:
Trans. Moscow Math. Soc. 2019, 251-294
A novel approach to critical-contrast homogenisation is proposed. Norm-resolvent asymptotics are explicitly constructed. An essential feature of our approach is that it relates homogenisation limits to a class of time-dispersive media.
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Externí odkaz:
http://arxiv.org/abs/1805.00884
This work deals with decay bounds for Green matrices and generalized eigenvectors of block Jacobi matrices when the real part of the spectral parameter lies in an infinite gap of the operator's essential spectrum. We consider the cases of commutative
Externí odkaz:
http://arxiv.org/abs/1801.01924
Autor:
Kupin, Stanislas, Naboko, Sergey
We are interested in the phenomenon of the essential spectrum instability for a class of unbounded (block) Jacobi matrices. We give a series of sufficient conditions for the matrices from certain classes to have a discrete spectrum on a half-axis of
Externí odkaz:
http://arxiv.org/abs/1709.05726
Publikováno v:
Studia Mathematica 242 (2) (2018)
For an arbitrary Hermitian period-$T$ Jacobi operator, we assume a perturbation by a Wigner-von Neumann type potential to devise subordinate solutions to the formal spectral equation for a (possibly infinite) real set, $S$, of the spectral parameter.
Externí odkaz:
http://arxiv.org/abs/1703.10223
Let $A$ and $(-\widetilde{A})$ be dissipative operators on a Hilbert space $\mathcal{H}$ and let $(A,\widetilde{A})$ form a dual pair, i.e. $A\subset\widetilde{A}^*$, resp.\ $\widetilde{A}\subset A^*$. We present a method of determining the proper di
Externí odkaz:
http://arxiv.org/abs/1603.08192