Results 31 to 40 of about 441 (58)

Asymptotic parabolicity for strongly damped wave equations

open access: yes, 2013
For $S$ a positive selfadjoint operator on a Hilbert space, \[ \frac{d^2u}{dt}(t) + 2 F(S)\frac{du}{dt}(t) + S^2u(t)=0 \] describes a class of wave equations with strong friction or damping if $F$ is a positive Borel function.
Fragnelli, Genni   +3 more
core   +1 more source

Jensen's Operator Inequality

open access: yes, 2002
We establish what we consider to be the definitive versions of Jensen's operator inequality and Jensen's trace inequality for functions defined on an interval.
Hansen, Frank, Pedersen, Gert K.
core   +1 more source

Further refinements of the Cauchy-Schwarz inequality for matrices [PDF]

open access: yes, 2014
Let $A, B$ and $X$ be $n\times n$ matrices such that $A, B$ are positive semidefinite. We present some refinements of the matrix Cauchy-Schwarz inequality by using some integration techniques and various refinements of the Hermite--Hadamard inequality ...
Bakherad, Mojtaba
core  

Some operator Bellman type inequalities

open access: yes, 2015
In this paper, we employ the Mond--Pe\v{c}ari\'c method to establish some reverses of the operator Bellman inequality under certain conditions. In particular, we show \begin{equation*} \delta I_{\mathscr K}+\sum_{j=1}^n\omega_j\Phi_j\left((I_{\mathscr H}-
Bakherad, Mojtaba, Morassaei, Ali
core   +1 more source

Exponentials of Normal Operators and Commutativity of Operators: A New Approach

open access: yes, 2011
We present a new approach to the question of when the commutativity of operator exponentials implies that of the operators. This is proved in the setting of bounded normal operators on a complex Hilbert space.
Mortad, Mohammed Hichem
core   +1 more source

Exponentials of Bounded Normal Operators

open access: yes, 2012
The present paper is mainly concerned with equations involving exponentials of bounded normal operators. Conditions implying commutativity of those normal operators are given. This is carried out without the known $2\pi i$-congruence-free hypothesis.
Chaban, Aicha, Mortad, Mohammed Hichem
core   +1 more source

Generation of subordinated holomorphic semigroups via Yosida's theorem

open access: yes, 2014
Using functional calculi theory, we obtain several estimates for $\|\psi(A)g(A)\|$, where $\psi$ is a Bernstein function, $g$ is a bounded completely monotone function and $-A$ is the generator of a holomorphic $C_0$-semigroup on a Banach space, bounded ...
Gomilko, Alexander, Tomilov, Yuri
core   +1 more source

Estimates for functions of the Laplacian on manifolds with bounded geometry

open access: yes, 2008
In this paper we consider a complete connected noncompact Riemannian manifold M with Ricci curvature bounded from below and positive injectivity radius. Denote by L the Laplace-Beltrami operator on M.
Mauceri, G., Meda, S., Vallarino, M.
core   +1 more source

Fractional Powers of Almost Non-Negative Operators [PDF]

open access: yes, 2005
Mathematics Subject Classification: Primary 47A60, 47D06.In this paper, we extend the theory of complex powers of operators to a class of operators in Banach spaces whose spectrum lies in C \ ]−∞, 0[ and whose resolvent satisfies an estimate ||(λ + A ...
Martínez, Celso   +2 more
core  

Noncommutative Chebyshev inequality involving the Hadamard product

open access: yes, 2018
We present several operator extensions of the Chebyshev inequality for Hilbert space operators. The main version deals with the synchronous Hadamard property for Hilbert space operators.
Bakherad, Mojtaba   +1 more
core  

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