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Let $\|\cdot\|_{\mathbf A}$ be a norm on $\mathbb C^m$ given by the formula $\|(z_1,\ldots,z_m)\|_{\mathbf A}=\|z_1A_1+\cdots+z_mA_m\|_{\rm op}$ for some choice of an $m$-tuple of $n\times n$ linearly independent matrices $\mathbf A=(A_1,…

Functional Analysis · Mathematics 2014-08-12 Avijit Pal

We extend the range of parameters associated with the Gagliardo-Nirenberg interpolation inequalities in the fractional Coulomb-Sobolev spaces for radial functions. We also study the optimality of this newly extended range of parameters.

Analysis of PDEs · Mathematics 2024-06-12 Arka Mallick , Hoai-Minh Nguyen

This paper establishes several new inequalities for the $A$-norm and $A$-numerical radius of operator sums in semi-Hilbertian spaces, significantly advancing the existing theory. We present two fundamental refinements of the generalized…

Functional Analysis · Mathematics 2025-07-09 M. H. M. Rashid

Let $X$ be a compact metric space, let $A$ be a unital AH algebra with large matrix sizes, and let $B$ be a stably finite unital C*-algebra. Then we give a lower bound for the radius of comparison of $C(X) \otimes B$ and prove that the…

Operator Algebras · Mathematics 2020-04-08 Mohammad B. Asadi , M. Ali Asadi-Vasfi

Let $ \mathcal{S}(p) $ be the class of all meromorphic univalent functions defined in the unit disc $ \mathbb{D} $ of the complex plane with a simple pole at $ z=p $ and normalized by the conditions $ f(0)=0 $ and $ f^{\prime}(0)=1 $. In…

Complex Variables · Mathematics 2024-07-02 Molla Basir Ahamed , Rajesh Hossain

The main goal of this article is to establish several new $\mathbb{A}$-numerical radius equalities and inequalities for $n\times n$ cross-diagonal, left circulant, skew left circulant operator matrices, where $\mathbb{A}$ is the $n\times n$…

Functional Analysis · Mathematics 2023-12-20 Soumitra Daptari , Fuad Kittaneh , Satyajit Sahoo

Assuming a unitarily invariant norm $|||\cdot|||$ is given on a two-sided ideal of bounded linear operators acting on a separable Hilbert space, it induces some unitarily invariant norms $|||\cdot|||$ on matrix algebras $\mathcal{M}_n$ for…

Functional Analysis · Mathematics 2015-11-09 Jagjit Singh Matharu , Mohammad Sal Moslehian

In this paper, we prove results on the relative radius of comparison of C*-algebras and their crossed products, focusing on the non-unital setting. More precisely, let $A$ be a stably finite simple non-type-I (not necessarily unital)…

Operator Algebras · Mathematics 2025-05-05 M. Ali Asadi-Vasfi , George A. Elliott

In this paper we derive some Edmundson-Lah-Ribaric type inequalities for positive linear functionals and n-convex functions. Main results are applied to the generalized f-divergence functional. Examples with Zipf-Mandelbrot law are used to…

Classical Analysis and ODEs · Mathematics 2021-01-26 Rozarija Mikić , Josip Pečarić , Djilda Pečarić

Using integral representations of the fractional power of matrices, and the geometric intuition of sectorial matrices, we show that for any accretive-dissipative matrix $A$ and any $t \in (0,1)$, the matrix \(A^t\) is accretive-dissipative,…

Functional Analysis · Mathematics 2025-09-30 Eman Aldabbas , Mohammad Sababheh

Let $\mathcal{H}$ be a complex Hilbert space and let $A$ be a positive operator on $\mathcal{H}$. We obtain new bounds for the $A$-numerical radius of operators in semi-Hilbertian space $\mathcal{B}_A(\mathcal{H})$ that generalize and…

Functional Analysis · Mathematics 2024-08-14 Pintu Bhunia , Raj Kumar Nayak , Kallol Paul

We show that Caffarelli-Kohn-Nirenberg first order interpolation inequalities as well as weighted trace inequalities in $\mathbb{R}^n \times \mathbb{R}_+$ admit a better range of power weights if we restrict ourselves to the space of…

Classical Analysis and ODEs · Mathematics 2010-09-03 Pablo L. De Nápoli , Irene Drelichman , Ricardo G. Durán

For positive definite matrices $A$ and $B$, the Araki-Lieb-Thirring inequality amounts to an eigenvalue log-submajorisation relation for fractional powers $$\lambda(A^t B^t) \prec_{w(\log)} \lambda^t(AB), \quad 0<t\le 1,$$ while for…

Functional Analysis · Mathematics 2013-04-23 Koenraad M. R. Audenaert

Suppose $\mathcal{H}_1, \mathcal{H}_2, \ldots, \mathcal{H}_n$ are arbitrary complex Hilbert spaces, and ${\bf A}=[A_{ij}]$ is an $n\times n$ operator matrix with $A_{ij}\in \mathcal{B}(\mathcal{H}_j, \mathcal{H}_i).$ We show that $w({\bf…

Functional Analysis · Mathematics 2025-03-05 Pintu Bhunia

Utilizing the linking algebra of a Hilbert $C^*$-module $\big(\mathscr{V}, {\|\!\cdot\!\|}\big)$, we introduce $\Omega(x)$ as a definition of numerical radius for an element $x\in\mathscr{V}$ and then show that $\Omega(\cdot)$ is a norm on…

Functional Analysis · Mathematics 2021-12-01 Ali Zamani

Let $a, b,c $ and $k$ be positive integers such that $1\leq a\leq b,a<c<2(a+b), c\ne b$ and $(a,b,c)=1$. Define the arithmetic function $f_k(a,b;c;n)$ by $$ \sum_{n=1}^{\infty}\frac{f_k(a,b;c;n)}{n^s}=\frac{\zeta (as)\zeta…

Number Theory · Mathematics 2013-01-22 Xiaodong Cao , Wenguang Zhai

We study the ratio of harmonic functions $u,v$, which have the same zero set $Z$ in the unit ball $B\subset \mathbb{R}^n$. The ratio $f=u/v$ can be extended to a real analytic nowhere vanishing function in $B$. We prove the Harnack…

Analysis of PDEs · Mathematics 2017-02-17 Alexander Logunov , Eugenia Malinnikova

We prove new inequalities for the spectral radius, essential spectral radius, operator norm, measure of noncompactness and numerical radius of Hadamard weighted geometric means of positive kernel operators on Banach function and sequence…

Functional Analysis · Mathematics 2022-02-01 Katarina Bogdanović , Aljoša Peperko

We obtain new parametric quadrature formulas with variable nodes for integrals of complex rational functions over circles, segments of the real axis and the real axis itself. Basing on these formulas we derive $(q,p)$-inequalities of…

Classical Analysis and ODEs · Mathematics 2018-01-18 Petr Chunaev , Vladimir Danchenko

Let $A$ be a positive (semidefinite) bounded linear operator acting on a complex Hilbert space $\big(\mathcal{H}, \langle \cdot\mid \cdot\rangle \big)$. The semi-inner product ${\langle x\mid y\rangle}_A := \langle Ax\mid y\rangle$, $x,…

Functional Analysis · Mathematics 2020-04-01 Kais Feki