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In this paper, we continue to develop the theory of free holomorphic functions on noncommutative regular polydomains. We find analogues of several classical results from complex analysis such as Abel theorem, Hadamard formula, Cauchy…

Functional Analysis · Mathematics 2017-05-09 Gelu Popescu

We establish a new description of the Schur-Agler norm of a holomorphic function on the polydisc as the solution of a convex optimization problem. Consequences of this description are explored both from a theoretical and from a practical…

Functional Analysis · Mathematics 2026-02-17 Michael Hartz , Yi Wang

There is a known generalization of the classical Schwarz lemma to holomorphic functions from the polydisk to the disk. In this paper, we characterize those functions which satisfy equality everywhere in this generalized inequality: they are…

Complex Variables · Mathematics 2013-02-06 Greg E. Knese

The classical theory of free analysis generalizes the noncommutative (nc) polynomials and rational functions, easily providing such results as an nc analogue of the Jacobian conjecture. However, the classical theory misses out on important…

Category Theory · Mathematics 2025-06-03 Julian Bushelli

We define a free holomorphic function to be a function that is locally a bounded nc-function. We prove that free holomorphic functions are the functions that are locally uniformly approximable by free polynomials. We prove a realization…

Operator Algebras · Mathematics 2013-07-03 Jim Agler , John E. McCarthy

A Herglotz function is a holomorphic map from the open complex unit disk into the closed complex right halfplane. A classical Herglotz function has an integral representation against a positive measure on the unit circle. We prove a free…

Operator Algebras · Mathematics 2020-05-26 J. E. Pascoe , Benjamin Passer , Ryan Tully-Doyle

We characterize the zero sets of functions in the Schur--Agler class over the unit polydisk as well as functions in the unit ball of the multiplier algebra of the Drury--Arveson space via operators associated with a unitary realization…

Complex Variables · Mathematics 2025-10-15 Poornendu Kumar , Jeet Sampat

We enhance the approximation capabilities of algebraic polynomials by composing them with homeomorphisms. This composition yields families of functions that remain dense in the space of continuous functions, while enabling more accurate…

Numerical Analysis · Mathematics 2025-12-17 Álvaro Fernández Corral , Yahya Saleh

We establish a theory of NC functions on a class of von Neumann algebras with a particular direct sum property, e.g. $B(\mathcal{H})$. In contrast to the theory's origins, we do not rely on appealing to results from the matricial case. We…

Operator Algebras · Mathematics 2021-07-29 Meric Augat , John E. McCarthy

In this paper, we study free holomorphic functions on regular polyballs and provide analogues of several classical results from complex analysis such as: Abel theorem, Hadamard formula, Cauchy inequality, Schwarz lemma, and maximum…

Operator Algebras · Mathematics 2015-03-02 Gelu Popescu

We investigate asymptotic polynomial approximation for a class of weighted Bloch functions in the unit disc. Our main result is a structural theorem on asymptotic polynomial approximation in the unit disc, in the flavor of the classical…

Complex Variables · Mathematics 2024-03-14 Adem Limani

One of the main applications of free probability is to show that for appropriately chosen independent copies of $d$ random matrix models, any noncommutative polynomial in these $d$ variables has a spectral distribution that converges…

Operator Algebras · Mathematics 2023-10-25 Benoît Collins , Tobias Mai , Akihiro Miyagawa , Félix Parraud , Sheng Yin

We present an approximation theorem for continuous non-decreasing functions on compact preordered spaces, leading to an algebraic characterization of their corresponding function spaces. As an application, we prove that the family of…

Functional Analysis · Mathematics 2025-12-04 Ettore Minguzzi

We present a general framework, treating Lipschitz domains in Riemannian manifolds, that provides conditions guaranteeing the existence of norming sets and generalized local polynomial reproduction - a powerful tool used in the analysis of…

Classical Analysis and ODEs · Mathematics 2025-11-11 Thomas Hangelbroek , Christian Rieger , Grady B. Wright

We prove a sharp Schwarz-type lemma for meromorphic functions with spherical derivative uniformly bounded away from zero. As a consequence we deduce an improved quantitative version of a recent normality criterion due to Grahl & Nevo and…

Complex Variables · Mathematics 2020-03-04 Richard Fournier , Daniela Kraus , Oliver Roth

Let $E$ be a closed subset of the unit circle of measure zero. Recently, Beise and M\"uller showed the existence of a function in the Hardy space $H^2$ for which the partial sums of its Taylor series approximate any continuous function on…

Complex Variables · Mathematics 2019-05-21 Catherine Bénéteau , Oleg Ivrii , Myrto Manolaki , Daniel Seco

We study the asymptotics of Schur polynomials with partitions $\lambda$ which are almost staircase; more precisely, partitions that differ from $((m-1)(N-1),(m-1)(N-2),\ldots,(m-1),0)$ by at most one component at the beginning as…

Probability · Mathematics 2020-09-01 Zhongyang Li

We introduce and study a generalization $s_{(\mu|\lambda)}$ of the Schur functions called the almost symmetric Schur functions. These functions simultaneously generalize the finite variable key polynomials and the infinite variable Schur…

Combinatorics · Mathematics 2024-05-03 Milo Bechtloff Weising

The class of Schur-Agler functions over a domain ${\mathcal D} \subset {\mathbb C}^{d}$ is defined as the class of holomorphic operator-valued functions on ${\mathcal D}$ for which a certain von Neumann inequality is satisfied when a…

Functional Analysis · Mathematics 2007-05-23 Joseph A. Ball , Vladimir Bolotnikov

In this paper we give a symbolical formula and a cancellation-free formula for the Schur elements associated to the simple modules of the degenerate cyclotomic Hecke algebras. As some direct applications, we show that the Schur elements are…

Representation Theory · Mathematics 2013-12-16 Deke Zhao
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