Results 31 to 40 of about 478,994 (322)

Approximation numbers of composition operators on Hp

Concrete Operators, 2015
give estimates for the approximation numbers of composition operators on the Hp spaces, 1 ≤ p < ∞
Li Daniel, Queffélec Hervé, Rodríguez-Piazza Luis   +2 more
doaj   +1 more source

Composite operators in QCD [PDF]

Nuclear Physics B, 1992
We give a formula for the derivatives of a correlation function of composite operators with respect to the parameters (i.e., the strong fine structure constant and the quark mass) of QCD in four-dimensional euclidean space. The formula is given as spatial integration of the operator conjugate to a parameter. The operator product of a composite operator
openaire   +2 more sources

Jan Stochel, a stellar mathematician [PDF]

Opuscula Mathematica
The occasion for this survey article was the 70th birthday of Jan Stochel, professor at Jagiellonian University, former head of the Chair of Functional Analysis and a prominent member of the Kraków school of operator theory.
Sameer Chavan, Raúl Curto, Zenon Jan Jabłoński, Il Bong Jung, Mihai Putinar   +4 more
doaj   +1 more source

Universal composition operators

Journal of Operator Theory, 2021
A Hilbert space operator U is called \textit{universal} (in the sense of Rota) if every Hilbert space operator is similar to a multiple of U restricted to one of its invariant subspaces. It follows that the \textit{invariant subspace problem} for Hilbert spaces is equivalent to the statement that all minimal invariant subspaces for U are one ...
Carmo, João R., Noor, S. Waleed
openaire   +2 more sources

Composition-Differentiation Operator on the Bergman Space

Pan-American Journal of Mathematics, 2023
We investigate the properties of composition-differentiation operator Dψ on the Bergman space of the unit disk L2a(D). Specifically, we characterize the properties of the reproducing kernel for the derivatives of the Bergman space functions. Moreover, we
K. O. Aloo, J. O. Bonyo, I. Okello
doaj   +1 more source

Fourier-integral-operator approximation of solutions to first-order hyperbolic pseudodifferential equations I: convergence in Sobolev spaces

, 2005
An approximation Ansatz for the operator solution, $U(z',z)$, of a hyperbolic first-order pseudodifferential equation, $\d_z + a(z,x,D_x)$ with $\Re (a) \geq 0$, is constructed as the composition of global Fourier integral operators with complex phases ...
Rousseau, Jerome Le
core   +5 more sources

Hypercyclic Composition Operators

Journal of Vasyl Stefanyk Precarpathian National University, 2015
In this paper we give survey of hypercyclic composition operators. In pacticular,we represent new classes of hypercyclic composition operators on the spaces of analyticfunctions
openaire   +3 more sources

Isometric multiplication operators and weighted composition operators of BMOA

Journal of Inequalities and Applications, 2021
Let u be an analytic function in the unit disk D $\mathbb{D}$ and φ be an analytic self-map of D $\mathbb{D}$ . We give characterizations of the symbols u and φ for which the multiplication operator M u $M_{u}$ and the weighted composition operator M u ,
Ligang Geng
doaj   +1 more source

Spectral stability of nonlinear waves in KdV-type evolution equations

, 2013
This paper concerns spectral stability of nonlinear waves in KdV-type evolution equations. The relevant eigenvalue problem is defined by the composition of an unbounded self-adjoint operator with a finite number of negative eigenvalues and an unbounded ...
ANGULO, ANGULO PAVA, ANGULO PAVA, BONA, BRIDGES, BRIDGES, BRONSKI, CHAMPNEYS, CHARDARD, CHUGUNOVA, CHUGUNOVA, CHUGUNOVA, CRAIG, CUCCAGNA, DIAS, GRILLAKIS, HAKKAEV, HARAGUS, ILLICHEV, KAPITULA, KAPITULA, KAPITULA, KICHENASSAMY, KODAMA, KOLLAR, LEVANDOVSKY, LIN, MADDOCKS, PEGO, PEGO, PELINOVSKY, PELINOVSKY, PELINOVSKY, PONTRYAGIN, SOUGANIDIS, STANISLAVOVA, WEINSTEIN   +36 more
core   +1 more source

Dexamethasone for Chemotherapy‐Induced Nausea and Vomiting Prevention in Pediatric Patients: International Consensus

Pediatric Blood &Cancer, EarlyView.
ABSTRACT Background An international Delphi panel of experts developed consensus statements to delineate the circumstances where the risks of dexamethasone as an antiemetic do and do not outweigh its benefits. Procedure Experts in supportive care of pediatric patients were invited to participate.
Negar Shavandi, Paula D. Robinson, Shana Jacobs, L. Lee Dupuis, the International Pediatric Dexamethasone Panel, Sameer Bakhshi, Tiene Bauters, Eva Brack, Simone Cesaro, Claire Fosbrook, Jason Freedman, Tamara MacDonald, Eloise Neumann, Venkatraman Radhakrishnan, Rod Rassekh, Florian Slimano, Johnathan Soggee, Joel Thompson, Marianne van de Wetering, Milena Villarroel, Jasper Wong   +20 more
wiley   +1 more source