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We investigate the closed convex hull of unitary orbits of selfadjoint elements in arbitrary unital C*-algebras. Using a notion of majorization against unbounded traces, a characterization of these closed convex hulls is obtained.…

Operator Algebras · Mathematics 2016-08-16 Ping Wong Ng , Leonel Robert , Paul Skoufranis

In this paper, we consider the Ma-Minda classes of analytic functions $\mathcal{S}^{*}(\phi):= \{f\in \mathcal{A} : ({zf'(z)}/{f(z)}) \prec \phi(z) \}$ and $\mathcal{C}(\phi):= \{f\in \mathcal{A} : (1+{zf''(z)}/{f'(z)}) \prec \phi(z) \}$…

Complex Variables · Mathematics 2023-07-25 S. Sivaprasad Kumar , Kamaljeet Gangania

In this paper, by using the concept of positive elements of $C^*$-algebras instead of the real numbers $\mathbb{R}$, a generalization of distribution functions, with a particular focus on distance distribution functions has been introduced…

Operator Algebras · Mathematics 2025-09-23 Rasoul Abazari

We write arbitrary separable nuclear C*-algebras as limits of inductive systems of finite-dimensional C*-algebras with completely positive connecting maps. The characteristic feature of such CPC*-systems is that the maps become more and…

Operator Algebras · Mathematics 2024-10-10 Kristin Courtney , Wilhelm Winter

We establish formulas for the $b$-adic Walsh coefficients of functions in $C^\alpha[0,1]$ for an integer $\alpha \geq 1$ and give upper bounds on the Walsh coefficients of these functions. We also study the Walsh coefficients of periodic…

Numerical Analysis · Mathematics 2025-12-02 Kosuke Suzuki , Takehito Yoshiki

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

We study properties of $\mathcal{A}$-harmonic and $\mathcal{A}$-superharmonic functions involving an operator having generalized Orlicz-growth embracing besides Orlicz case also natural ranges of variable exponent and double-phase cases. In…

Analysis of PDEs · Mathematics 2020-06-26 Iwona Chlebicka , Anna Zatorska-Goldstein

The C*-envelope of the limit algebra (or limit space) of a contractive regular system of digraph algebras (or digraph spaces) is shown to be an approximately finite C*-algebra and the direct system for the C*-envelope is determined…

funct-an · Mathematics 2008-02-03 C. Laurie , S. C. Power

We generalize several inequalities involving powers of the numerical radius for off-diagonal part of $2\times2$ operator matrices of the form $T=\left[\begin{array}{cc} 0&B, C&0 \end{array}\right]$, where $B, C$ are two operators. In…

Functional Analysis · Mathematics 2017-06-19 Monire Hajmohamadi , Rahmatollah Lashkaripour , Mojtaba Bakherad

On a discrete group G a length function may implement a spectral triple on the reduced group C*-algebra. Following A. Connes, the Dirac operator of the triple then can induce a metric on the state space of reduced group C*-algebra. Recent…

Operator Algebras · Mathematics 2007-05-23 Cristina Antonescu , Erik Christensen

In this paper, we present several sharp upper bounds for the numerical radii of the diagonal and off-diagonal parts of the $2\times2$ block operator matrix $\begin{bmatrix}A&B\\ C&D\end{bmatrix}$. Among extensions of some results of…

Functional Analysis · Mathematics 2018-11-01 M. Ghaderi Aghideh , M. S. Moslehian , J. Rooin

We study the relations between boundaries for algebras of holomorphic functions on Banach spaces and complex convexity of their balls. In addition, we show that the Shilov boundary for algebras of holomorphic functions on an order…

Functional Analysis · Mathematics 2007-08-31 Yun Sung Choi , Kwang Hee Han , Han Ju Lee

We provide some background on the category of classifiable $\mathrm{C}^*$-algebras, whose objects are infinite-dimensional, simple, separable, unital $\mathrm{C}^*$-algebras that have finite nuclear dimension and satisfy the universal…

Operator Algebras · Mathematics 2025-12-09 Bhishan Jacelon

In this paper, we investigate the boundedness of maximal operator and its commutators in generalized Orlicz-Morrey spaces on the spaces of homogeneous type. As an application of this boundedness, we give necessary and sufficient condition…

Functional Analysis · Mathematics 2018-04-25 Vagif S. Guliyev , Fatih Deringoz

Some elementary inequalities providing upper bounds for the difference of the norm and the numerical radius of a bounded linear operator on Hilbert spaces under appropriate conditions are given.

Functional Analysis · Mathematics 2007-05-23 Sever Silvestru Dragomir

We establish new upper bounds for the numerical radius of bounded linear operators on a complex Hilbert space by introducing weighted geometric means of the modulus of an operator and its adjoint. This approach yields a family of…

Functional Analysis · Mathematics 2026-02-05 Shankhadeep Mondal , Ram Narayan Mohapatra , Kasun Tharuka Dewage

This paper develops the geometry of locally bounded rational functions on non-singular real algebraic varieties. First various basic geometric and algebraic results regarding these functions are established in any dimension, culminating…

Algebraic Geometry · Mathematics 2024-10-15 Victor Delage , Goulwen Fichou , Aftab Patel

In this paper we show that, using combinatorial inequalities and Matrix-Averages, we can generate Musielak-Orlicz spaces, i.e., we prove that $1/\pi \sum_{\pi} \max\limits_{1 \leq i \leq n} \abs{x_i y_{i\pi(i)}} \sim \norm{x}_{\Sigma M_i}$,…

Functional Analysis · Mathematics 2012-08-09 Joscha Prochno

Let $(\Omega,\Sigma,\mu)$ be a $\sigma$-finite complete measure space, $\tau:\Omega\rightarrow\Omega$ be a measurable transformation and $\phi$ be an Orlicz function. In this article, first a necessary and sufficient condition for the…

Functional Analysis · Mathematics 2016-06-13 Ratan Kumar Giri , Shesadev Pradhan

The numerical range of holomorphic mappings arises in many aspects of nonlinear analysis, finite and infinite dimensional holomorphy, and complex dynamical systems. In particular, this notion plays a crucial role in establishing exponential…

Complex Variables · Mathematics 2015-11-12 Filippo Bracci , Marina Levenshtein , Simeon Reich , David Shoikhet
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