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Related papers: Real complex functions

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We initiate and study the theory of ``real decomposable maps" between real operator systems. Formally, this is new even in the complex case, which hitherto has restricted itself to the case where the systems are complex C*-algebras. We…

Operator Algebras · Mathematics 2026-05-11 David P. Blecher , Christiaan H. Pretorius

In this paper we present a result about analytic functions f defined on the open unit disc and with a finite number of exceptional values containedin the real interval (0, 1). We find an upper bound for the modulus of f' in 0. This bound is…

Complex Variables · Mathematics 2011-01-28 André Gomes

Orthogonal rational functions (ORF) on the unit circle generalize orthogonal polynomials (poles at infinity) and Laurent polynomials (poles at zero and infinity). In this paper we investigate the properties of and the relation between these…

Numerical Analysis · Mathematics 2017-12-05 Adhemar Bultheel , Ruyman Cruz-Barroso , Andreas Lasarow

We develop a general theory of operator realizations, or ``linear representations" of analytic functions in several non-commuting variables about a matrix-centre. In particular we show that a non-commutative function has a matrix-centre…

Functional Analysis · Mathematics 2025-09-12 Ali Karoobi , Robert T. W. Martin , Maximilian Tornes

Operator $k$-tone functions on an open interval of the real line, which are higher order extensions of operator monotone and convex functions, are characterized via certain inequalities for the real and imaginary parts of analytic…

Functional Analysis · Mathematics 2015-08-25 Fumio Hiai

We develop contractive finite dimensional realizations for rational matrix functions of one variable on domains that are not simply connected, such as the annulus. The proof uses multivariable contractive realization results as well as…

Functional Analysis · Mathematics 2025-04-07 Radomił Baran , Piotr Pikul , Hugo J. Woerdeman , Michał Wojtylak

The aim of this paper is two fold. We show that if a complex function $F$ on $\C$ operates in the modulation spaces $M^{p,1}(\R^n)$ by composition, then $F$ is real analytic on $\R^2 \approx \C$. This answers negatively, the open question…

Analysis of PDEs · Mathematics 2014-12-02 Divyang G. Bhimani , P. K. Ratnakumar

We define an extension of operator-valued positive definite functions from the real or complex setting to topological algebras, and describe their associated reproducing kernel spaces. The case of entire functions is of special interest,…

Functional Analysis · Mathematics 2024-01-05 Daniel Alpay , Ismael L. Paiva

In this paper the spectrum of composition operators on the space of real analytic functions is investigated. In some cases it is completely determined while in some other cases it is only estimated.

Functional Analysis · Mathematics 2016-09-06 José Bonet , Paweł Domański

The present article is an extended version of [6] containing new results and an updated list of references. We review the notion of polar analyticity introduced in a previous paper and succesfully applied in Mellin analysis and quadrature…

Complex Variables · Mathematics 2018-05-04 Carlo Bardaro , Paul. L. Butzer , Ilaria Mantellini , Gerhard Schmeisser

We give a classification of unitary representations of certain Polish, not necessarily locally compact, groups: the groups of all measurable functions with values in the circle and the groups of all continuous functions on compact, second…

Representation Theory · Mathematics 2014-09-23 Slawomir Solecki

Many different types of fractional calculus have been proposed, which can be organised into some general classes of operators. For a unified mathematical theory, results should be proved in the most general possible setting. Two important…

Classical Analysis and ODEs · Mathematics 2021-01-12 Christian Maxime Steve Oumarou , Hafiz Muhammad Fahad , Jean-Daniel Djida , Arran Fernandez

We study the Banach algebras of bounded holomorphic functions on the unit disk whose boundary values, having, in a sense, the weakest possible discontinuities, belong to the algebra of semi-almost periodic functions on the unit circle. The…

Complex Variables · Mathematics 2009-11-06 A. Brudnyi , D. Kinzebulatov

In this work, we define a new class of fractional analytic functions containing functional parameters in the open unit disk. By employing this class, we introduce two types of fractional operators, differential and integral. The fractional…

Functional Analysis · Mathematics 2016-01-14 Rabha W. Ibrahim , Adem Kilicman , Zainab E. Abdulnaby

Analytic properties of function spaces over the real and the complex fields are different in some ways. This reflects in algebraic properties which are different at times and similar in some other respects. For instance, the ring of…

Rings and Algebras · Mathematics 2017-09-22 Vaibhav Pandey , Sagar Shrivastava , B. Sury

In this article, we will showcase some analytical concepts that can be used to tackle Functional Equations (FE) in the positive real numbers domain. Such concepts and related techniques have occasionally appeared in recent High School Math…

History and Overview · Mathematics 2023-11-21 Konstantinos Konstantinidis

In this paper, by making use of a certain family of fractional derivative operators in the complex domain, we introduce and investigate a new subclass $\mathcal{P}_{\tau,\mu}(k,\delta,\gamma)$ of analytic and univalent functions in the open…

Complex Variables · Mathematics 2015-11-06 Zainab Esa , H. M. Srivastava , Adem Kilicman , Rabha W. Ibrahim

The aim of this paper is to inter-relate several algebraic and analytic objects, such as real-type algebraic curves, quadrature domains, functions on them and rational matrix functions with special properties, and some objects from Operator…

Spectral Theory · Mathematics 2010-12-10 Dmitry V. Yakubovich

Composition operators with analytic symbols on some reproducing kernel Hilbert spaces of entire functions on a complex Hilbert space are studied. The questions of their boundedness, seminormality and positivity are investigated. It is…

Functional Analysis · Mathematics 2016-10-17 Jan Stochel , Jerzy B. Stochel

In our previous paper, Real Polynomials with a Complex Twist [see http://archives.math.utk.edu/ICTCM/VOL28/A040/paper.pdf], we used advancements in computer graphics that allow us to easily illustrate more complete graphs of polynomial…

History and Overview · Mathematics 2018-05-16 Michael Warren , John Gresham , Bryant Wyatt