Results 31 to 40 of about 220,336 (311)

Positively p-nuclear operators, positively p-integral operators and approximation properties [PDF]

Positivity, 2022
In the present paper, we introduce and investigate a new class of positively $p$-nuclear operators that are positive analogues of right $p$-nuclear operators. One of our main results establishes an identification of the dual space of positively $p$-nuclear operators with the class of positive $p$-majorizing operators that is a dual notion of positive ...
Dongyang Chen, Amar Belacel, Javier Alejandro Chávez-Domínguez   +2 more
openaire   +2 more sources

The spectrum of the force-based quasicontinuum operator for a homogeneous periodic chain [PDF]

, 2012
We show under general conditions that the linearized force-based quasicontinuum (QCF) operator has a real, positive spectrum. The spectrum is identical to that of the quasinonlocal quasicontinuum (QNL) operator in the case of second-neighbor interactions.
Ortner, C., Ortner, Christoph, Dobson, M., Shapeev, A. V., Dobson, Matthew   +4 more
core   +1 more source

$\mathcal{A}$-Joint Numerical Radius Bounds for Operator Pairs in Semi-Hilbert Spaces with Applications

Mathematics
Consider a complex Hilbert space X,⟨·,·⟩ equipped with a positive (semidefinite) bounded linear operator A on X. The A-joint numerical radius for two A-bounded operators T and S is defined as ωA,e(T,S)=sup∥x∥A=1⟨Tx,x⟩A2+⟨Sx,x⟩A2.
Amani Baazeem, Silvestru Sever Dragomir, Kais Feki   +2 more
doaj   +1 more source

Locally Eventually Positive Operator Semigroups

, 2021
We initiate a theory of locally eventually positive operator semigroups on Banach lattices. Intuitively this means: given a positive initial datum, the solution of the corresponding Cauchy problem becomes (and stays) positive in a part of the domain ...
Arora, Sahiba
core   +1 more source

Positive forms on Banach spaces

, 2003
The first representation theorem establishes a correspondence between positive, self-adjoint operators and closed, positive forms on Hilbert spaces.
Farkas, Bálint, Matolcsi, Máté, M. Matolcsi, B. Farkas   +3 more
core   +1 more source

A sufficient condition for the boundedness of operator-weighted martingale transforms and Hilbert transform [PDF]

, 2007
Let W be an operator weight taking values almost everywhere in the bounded positive invertible linear operators on a separable Hilbert space H. We show that if W and its inverse W−1 both satisfy a matrix reverse Holder property introduced in [2], then ...
Pott, S.
core   +1 more source

NEW MAJORIZATION FOR BOUNDED LINEAR OPERATORS IN HILBERT SPACES [PDF]

Journal of Algebraic Systems
‎This work aims to introduce and investigate a preordering in $B(\mathcal{H}),$‎ ‎the Banach space of all bounded linear operators defined on a complex‎ ‎Hilbert space $\mathcal{H}.$ It is called strong majorization and denoted by $S\prec_{s}T,$ for‎ ‎$S,
Farzaneh Gorjizadeh, Noha Eftekhari
doaj   +1 more source

Positive definiteness: from scalar to operator-valued kernels [PDF]

Surveys in Mathematics and its Applications, 2021
In this paper we present a short overview of results that provide relationships among scalar, matrix-valued and certain operator-valued positive definite kernels.
V. A. Menegatto
doaj  

Perturbation theory for the logarithm of a positive operator

Journal of High Energy Physics, 2023
In various contexts in mathematical physics, such as out-of-equilibrium physics and the asymptotic information theory of many-body quantum systems, one needs to compute the logarithm of a positive unbounded operator.
Nima Lashkari, Hong Liu, Srivatsan Rajagopal   +2 more
doaj   +1 more source

Carcinomas and Carcinoid Tumors of the Lungs and Bronchi in Children and Adolescents: The EXPeRT Recommendations

Pediatric Blood &Cancer, EarlyView.
ABSTRACT Primary lung carcinomas and bronchial carcinoid tumors (BC) are very rare malignancies in childhood. While typical BC and mucoepidermoid carcinomas are mostly low‐grade, localized tumors with a more favorable prognosis than in adults, necessitating avoidance of overtreatment, adenocarcinomas of the lung are often diagnosed at advanced disease ...
Michael Abele, Calogero Virgone, Michaela Kuhlen, Sabine Irtan, Yves Reguerre, Malgorzata Krawczyk, Ewa Bien, Tal Ben‐Ami, Maja Cesen, Ricardo Lopez‐Almaraz, Andrea Ferrari, Gianni Bisogno, Dominik T. Schneider, Abbas Agaimy, Constantin Lapa, Hubert Ducou le Pointe, Rainer Claus, Catherine Daniel, Ines B. Brecht, Daniel Orbach   +19 more
wiley   +1 more source