Results 11 to 20 of about 736 (56)

Complex interpolation with Dirichlet boundary conditions on the half line

open access: yesMathematische Nachrichten, Volume 291, Issue 16, Page 2435-2456, November 2018., 2018
Abstract We prove results on complex interpolation of vector‐valued Sobolev spaces over the half‐line with Dirichlet boundary condition. Motivated by applications in evolution equations, the results are presented for Banach space‐valued Sobolev spaces with a power weight. The proof is based on recent results on pointwise multipliers in Bessel potential
Nick Lindemulder   +2 more
wiley   +1 more source

The Cayley transform of Banach algebras

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 29, Issue 7, Page 427-428, 2002., 2002
The main result of Haynes (1991) is that a square matrix is convergent (limn→∞Dn = 0) if and only if it is the Cayley transform CA = (I−A)−1(I + A) of a stable matrix A. In this note, we show, with a simple proof, that the above is true in a much more general setting of complex Banach algebras.
Zhidong Pan
wiley   +1 more source

Continuity and general perturbation of the Drazin inverse for closed linear operators

open access: yesAbstract and Applied Analysis, Volume 7, Issue 6, Page 335-347, 2002., 2002
We study perturbations and continuity of the Drazin inverse of a closed linear operator A and obtain explicit error estimates in terms of the gap between closed operators and the gap between ranges and nullspaces of operators. The results are used to derive a theorem on the continuity of the Drazin inverse for closed operators and to describe the ...
N. Castro González   +2 more
wiley   +1 more source

Regularized functional calculi, semigroups, and cosine functions for pseudodifferential operators

open access: yesAbstract and Applied Analysis, Volume 2, Issue 1-2, Page 121-136, 1997., 1997
Let iAj(1 ≤ j ≤ n) be generators of commuting bounded strongly continuous groups, A ≡ (A1, A2, …, An). We show that, when f has sufficiently many polynomially bounded derivatives, then there exist k, r > 0 such that f(A) has a ‐regularized BCk(f(Rn)) functional calculus.
Ralph Delaubenfels, Yansong Lei
wiley   +1 more source

On the consequences of a Mihlin-H\"ormander functional calculus: maximal and square function estimates [PDF]

open access: yes, 2015
We prove that the existence of a Mihlin-H\"ormander functional calculus for an operator $L$ implies the boundedness on $L^p$ of both the maximal operators and the continuous square functions build on spectral multipliers of $L.$ The considered multiplier
Wróbel, Błażej
core   +2 more sources

Chebyshev type inequalities for Hilbert space operators [PDF]

open access: yes, 2014
We establish several operator extensions of the Chebyshev inequality. The main version deals with the Hadamard product of Hilbert space operators.
Mohammad Sal   +2 more
core   +1 more source

An asymmetric Kadison's inequality [PDF]

open access: yes, 2010
Some inequalities for positive linear maps on matrix algebras are given, especially asymmetric extensions of Kadison's inequality and several operator versions of Chebyshev's inequality. We also discuss well-known results around the matrix geometric mean
Bourin, Jean-Christophe, Ricard, Éric
core   +4 more sources

Spectral multipliers for Laplacians with drift on Damek-Ricci spaces [PDF]

open access: yes, 2013
We prove a multiplier theorem for certain Laplacians with drift on Damek-Ricci spaces, which are a class of Lie groups of exponential growth. Our theorem generalizes previous results obtained by W. Hebisch, G. Mauceri and S.
Ottazzi, Alessandro, Vallarino, Maria
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

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