Results 11 to 20 of about 76,262 (55)

Norm-parallelism in the geometry of Hilbert $C^*$-modules [PDF]

Indag. Math. (N.S.) 27 (2016), no. 1, 266-281, 2015
Utilizing the Birkhoff--James orthogonality, we present some characterizations of the norm-parallelism for elements of $\mathbb{B}(\mathscr{H})$ defined on a finite dimensional Hilbert space, elements of a Hilbert $C^*$-module over the $C^*$-algebra of compact operators and elements of an arbitrary $C^*$-algebra.
arxiv   +1 more source

About instability in an elastic Cosserat body with pores

Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica
This article is centered on the study of the isotropic, porous Cosserat elastic media, realized by means of a parallel with the media of the same type, but anisotropic, by following the rewriting in a new form of the equations that govern this theory ...
Codarcea-Munteanu L., Marin M., Abouelregal A. E.   +2 more
doaj   +1 more source

Exact and approximate operator parallelism [PDF]

Can. Math. Bull. 58 (2015) 207-224, 2014
Extending the notion of parallelism we introduce the concept of approximate parallelism in normed spaces and then substantially restrict ourselves to the setting of Hilbert space operators endowed with the operator norm. We present several characterizations of the exact and approximate operator parallelism in the algebra $\mathbb{B}(\mathscr{H})$ of ...
arxiv   +1 more source

Cartesian decomposition and Numerical radius inequalities [PDF]

Linear Algebra Appl. 471 (2015), 46--53, 2015
We show that if $T=H+iK$ is the Cartesian decomposition of $T\in \mathbb{B(\mathscr{H})}$, then for $\alpha ,\beta \in \mathbb{R}$, $\sup_{\alpha ^{2}+\beta ^{2}=1}\Vert \alpha H+\beta K\Vert =w(T)$. We then apply it to prove that if $A,B,X\in \mathbb{B(\mathscr{H})}$ and $0\leq mI\leq X$, then \begin{align*} m\Vert \mbox{Re}(A)-\mbox{Re}(B)\Vert ...
arxiv   +1 more source

On the metrizability of suprametric space

Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica
The question of metrizability of suprametric space is answered positively. The observed metric coincides with a suprametric in a way that convergence and continuity are preserved between suprametric space and associated metric space along with the ...
Karapınar Erdal, Cvetković Marija
doaj   +1 more source

Endpoint Estimates for N-dimensional Hardy Operators and Their Commutators [PDF]

Sci China Math 2012, 2011
In this paper, it is proved that the higher dimensional Hardy operator is bounded from Hardy space to Lebesgue space. The endpoint estimate for the commutator generated by Hardy operator and (central) BMO function is also discussed.
arxiv   +1 more source

Weak convergence theorems for inertial Krasnoselskii-Mann iterations in the class of enriched nonexpansive operators in Hilbert spaces

Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica
In this paper, we present some results about the aproximation of fixed points of nonexpansive and enriched nonexpansive operators. In order to approximate the fixed points of enriched nonexpansive mappings, we use the Krasnoselskii-Mann iteration for ...
Socaciu Liviu-Ignat
doaj   +1 more source

Operator inequalities related to the Corach--Porta--Recht inequality [PDF]

Linear Algebra Appl. 436 (2012), no. 9, 3008-3017, 2011
We prove some refinements of an inequality due to X. Zhan in an arbitrary complex Hilbert space by using some results on the Heinz inequality. We present several related inequalities as well as new variants of the Corach--Porta--Recht inequality. We also characterize the class of operators satisfying $\left\Vert SXS^{-1}+S^{-1}XS+kX\right\Vert \geq (k ...
arxiv  

XMO and Weighted Compact Bilinear Commutators [PDF]

arXiv, 2019
To study the compactness of bilinear commutators of certain bilinear Calder\'on--Zygmund operators which include (inhomogeneous) Coifman--Meyer bilinear Fourier multipliers and bilinear pseudodifferential operators as special examples, Torres and Xue [Rev. Mat. Iberoam.
arxiv  

Equivalence between estimates for quasi-commutators and commutators [PDF]

arXiv, 2017
In this short note we show that under some mild conditions on the space and the operators, an estimate for $\|Sf(A) - f(B)S\|$ needs only to be studied for invertible $S$ and $B$ equal to $A$. Thus estimates for a quasi-commutator can be derived from that for the commutator.
arxiv