Results 31 to 40 of about 70,365 (263)

Hamiltonians with Riesz Bases of Generalised Eigenvectors and Riccati Equations [PDF]

, 2010
An algebraic Riccati equation for linear operators is studied, which arises in systems theory. For the case that all involved operators are unbounded, the existence of infinitely many selfadjoint solutions is shown. To this end, invariant graph subspaces
Wyss, Christian
core   +1 more source

Weyl-von Neumann Theorem and Borel Complexity of Unitary Equivalence Modulo Compacts of Self-Adjoint Operators [PDF]

, 2014
Weyl-von Neumann Theorem asserts that two bounded self-adjoint operators $A,B$ on a Hilbert space $H$ are unitarily equivalent modulo compacts, i.e., $uAu^*+K=B$ for some unitary $u\in \mathcal{U}(H)$ and compact self-adjoint operator $K$, if and only if
Ando, Hiroshi, Matsuzawa, Yasumichi
core   +4 more sources

A new class of linear operators on ℓ2 and Schur multipliers for them

Journal of Function Spaces and Applications, 2007
We introduce the space Bw(ℓ2) of linear (unbounded) operators on ℓ2 which map decreasing sequences from ℓ2 into sequences from ℓ2 and we find some classes of operators belonging either to Bw(ℓ2) or to the space of all Schur multipliers on Bw(ℓ2).
Anca-Nicoleta Marcoci, Liviu-Gabriel Marcoci   +1 more
doaj   +1 more source

Asymptotically periodic behavior of solutions to fractional non-instantaneous impulsive semilinear differential inclusions with sectorial operators

Advances in Difference Equations, 2021
In this paper, we prove two results concerning the existence of S-asymptotically ω-periodic solutions for non-instantaneous impulsive semilinear differential inclusions of order 1 < α < 2 ...
Zainab Alsheekhhussain, JinRong Wang, Ahmed Gamal Ibrahim   +2 more
doaj   +1 more source

Unbounded well-bounded operators, strongly continuous semigroups and the Laplace transform [PDF]

Studia Mathematica, 1992
Summary: Suppose \(A\) is a (possibly unbounded) linear operator on a Banach space. We show that the following are equivalent. (1) \(A\) is well-bounded on \([0,\infty)\). (2) \(-A\) generates a strongly continuous semigroup \(\{e^{- sA}\}_{s\geq 0}\) such that \(\{(1/s^ 2) e^{-sA}\}_{s>0}\) is the Laplace transform of a Lipschitz continuous family of ...
openaire   +1 more source

Stability Conditions for Perturbed Semigroups on a Hilbert Space via Commutators

Communications in Advanced Mathematical Sciences, 2019
Let $A$ and $B$ be linear operators on a Hilbert space. Let $A$ and $A+B$ generate $C_0$-semigroups $e^{tA}$ and $e^{t(A+B)}$, respectively, and $e^{tA}$ be exponentially stable.
Michael Gil'
doaj   +1 more source

On Unbounded Composition Operators in $L^2$-Spaces

, 2012
Fundamental properties of unbounded composition operators in $L^2$-spaces are studied. Characterizations of normal and quasinormal composition operators are provided. Formally normal composition operators are shown to be normal.
A Brown, A Brown, A Daniluk, A Lambert, A Lambert, A Lambert, A Lambert, C Berg, Ch. Burnap, D Harrington, E Nordgren, EA Coddington, EA Coddington, FH Szafraniec, G Biriuk, Il Bong Jung, J Janas, J Stochel, J Stochel, J Stochel, J Stochel, J Stochel, J Stochel, J Stochel, J Weidmann, Jan Stochel, JB Conway, JT Campbell, K Schmüdgen, K Schmüdgen, K Schmüdgen, M.R. Embry-Wardrop, MM Rao, MR Embry, MR Embry-Wardrop, N Dunford, P Budzyński, P Dibrell, Piotr Budzyński, PR Halmos, PR Halmos, R Whitley, RK Singh, RK Singh, RK Singh, S Kouchekian, S Ôta, T. Veluchamy, W Mlak, W Rudin, Zenon Jan Jabłoński, ZJ Jabłonski, ZJ Jabłoński   +52 more
core   +2 more sources

An Epistemic Foundation for Authentication Logics (Extended Abstract) [PDF]

Electronic Proceedings in Theoretical Computer Science, 2017
While there have been many attempts, going back to BAN logic, to base reasoning about security protocols on epistemic notions, they have not been all that successful. Arguably, this has been due to the particular logics chosen.
Joseph Y. Halpern, Ron van der Meyden, Riccardo Pucella   +2 more
doaj   +1 more source

A Hybrid Method for All Types of Solutions of the System of Cauchy-Type Singular Integral Equations of the First Kind

Mathematics, 2023
In this note, the hybrid method (combination of the homotopy perturbation method (HPM) and the Gauss elimination method (GEM)) is developed as a semi-analytical solution for the first kind system of Cauchy-type singular integral equations (CSIEs) with ...
H. X. Mamatova, Z. K. Eshkuvatov, Sh. Ismail   +2 more
doaj   +1 more source

On exact controllability and complete stabilizability for linear systems

Visnik Harkivsʹkogo Nacionalʹnogo Universitetu im. V.N. Karazina. Cepiâ Matematika, Prikladna Matematika i Mehanika, 2021
In this paper we consider linear systems with control described by the equation $\dot x = \mathcal A x +\mathcal B u$ where functions u and x take values in U and X respectively.
Rabah Rabah
doaj   +1 more source