Results 31 to 40 of about 76,535 (61)

Refinements of Some Numerical radius inequalities for Hilbert Space Operators [PDF]

arXiv, 2018
In this work, some generalizations and refinements inequalities for numerical radius of the product of Hilbert space operators are proved. New inequalities for numerical radius of block matrices of Hilbert space operators are also established.
arxiv  

On the generalized mixed Schwarz inequality [PDF]

arXiv, 2018
In this work, an extension of the generalized mixed Schwarz inequality is proved. A companion of the generalized mixed Schwarz inequality is established by merging both Cartesian and Polar decompositions of operators. Based on that some numerical radius inequalities are proved.
arxiv  

Sharp Bounds for the Generalized Hardy Operators [PDF]

arXiv, 2011
We get the sharp bound for weak type $(1,1)$ inequality for $n$-dimensional Hardy operator. Moreover, the precise norms of generalized Hardy operators on the type of Campanato spaces are obtained. As applications, the corresponding norms of the Riemann-Liouville integral operator and $n$-dimensional Hardy operator are deduced.
arxiv  

Improved operator Kantorovich and Wielandt inequalities for positive linear maps [PDF]

arXiv, 2015
In this paper, we improve and generalize the operator versions of Kantorovich and Wielandt inequalities for positive linear maps on Hilbert space. Our results are more extensive and precise than many previous results due to Fu and He [Linear Multilinear Algebra, doi: 10. 1080/03081087. 2014. 880432.] and Zhang [Banach J. Math. Anal., 9 (2015), no.
arxiv  

On the real and imaginary parts of powers of the Volterra operator [PDF]

arXiv
We study the real and imaginary parts of the powers of the Volterra operator on $L^2[0,1]$, specifically their eigenvalues, their norms and their numerical ranges.
arxiv  

Spectral shorted operators [PDF]

arXiv, 2004
If $\mathcal H$ is a Hilbert space, $\mathcal S \subseteq \mathcal H$ is a closed subspace of $\mathcal H$, and $A $ is a positive bounded linear operator on $\mathcal H$, the spectral shorted operator $\rho(\mathcal S, A)$ is defined as the infimum of the sequence $\Sigma (\mathcal S, A^n)^{1/n}$, where $\Sigma (\mathcal S, B)$ denotes the shorted ...
arxiv  

Weighted projections and Riesz frames [PDF]

arXiv, 2004
Let $\mathcal{H}$ be a (separable) Hilbert space and $\{e_k\}_{k\geq 1}$ a fixed orthonormal basis of $\mathcal{H}$. Motivated by many papers on scaled projections, angles of subspaces and oblique projections, we define and study the notion of compatibility between a subspace and the abelian algebra of diagonal operators in the given basis.
arxiv  

Norm Inequalities in Operator Ideals [PDF]

arXiv, 2008
In this paper we introduce a new technique for proving norm inequalities in operator ideals with an unitarily invariant norm. Among the well known inequalities which can be proved with this technique are the L\"owner-Heinz inequality, inequalities relating various operator means and the Corach-Porta-Recht inequality.
arxiv  

Operator extensions of Hua's inequality [PDF]

Linear Alg. Appl. 430 (2009) 1131-1139, 2008
We give an extension of Hua's inequality in pre-Hilbert $C^*$-modules without using convexity or the classical Hua's inequality. As a consequence, some known and new generalizations of this inequality are deduced. Providing a Jensen inequality in the content of Hilbert $C^*$-modules, another extension of Hua's inequality is obtained. We also present an
arxiv  

Unitarily invariant norm inequalities for operators [PDF]

arXiv, 2011
We present several operator and norm inequalities for Hilbert space operators. In particular, we prove that if $A_{1},A_{2},...,A_{n}\in {\mathbb B}({\mathscr H})$, then \[|||A_{1}A_{2}^{*}+A_{2}A_{3}^{*}+...+A_{n}A_{1}^{*}|||\leq|||\sum_{i=1}^{n}A_{i}A_{i}^{*}|||,\] for all unitarily invariant norms.
arxiv