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Related papers: $q$-Rational functions and interpolation with comp…

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Given a domain $\Omega$ in $\mathbb{C}^m$, and a finite set of points $z_1,z_2,\ldots, z_n\in \Omega$ and $w_1,w_2,\ldots, w_n\in \mathbb{D}$ (the open unit disc in the complex plane), the \textit{Pick interpolation problem} asks when there…

Functional Analysis · Mathematics 2023-09-13 Tirthankar Bhattacharyya , Anindya Biswas , Vikramjeet Singh Chandel

Let K be a non archimedean algebraically closed field of characteristic pi complete for its ultrametric absolute value. In a recent paper by Escassut and Yang, polynomial decompositions P(f)=Q(g) for meromorphic functions f, g on K (resp.…

Complex Variables · Mathematics 2007-05-23 Eberhard Mayerhofer

We formulate three boundary Nevanlinna-Pick interpolation problems for generalized Nevanlinna functions. For each problem, we parameterize the set of all solutions in terms of a linear fractional transformation with an extended Nevanlinna…

Complex Variables · Mathematics 2007-05-23 Paul Anthony Smith

We prove that the Nevalinna-Pick algorithm provides different homeomorphisms between certain topological spaces of measures, analytic functions and sequences of complex numbers. This algorithm also yields a continued fraction expansion of…

Classical Analysis and ODEs · Mathematics 2007-11-06 Olav Njastad , Luis Velazquez

The classical $q$-analogue of the integers was recently generalized by Morier-Genoud and Ovsienko to give $q$-analogues of rational numbers. Some combinatorial interpretations are already known, namely as the rank generating functions for…

Combinatorics · Mathematics 2021-11-16 Nicholas Ovenhouse

Recent results of Davidson-Paulsen-Raghupathi-Singh give necessary and sufficient conditions for the existence of a solution to the Nevanlinna-Pick interpolation problem on the unit disk with the additional restriction that the interpolant…

Functional Analysis · Mathematics 2020-03-02 J. A. Ball , V. Bolotnikov , S. ter Horst

A seminal result of Agler characterizes the so-called Schur-Agler class of functions on the polydisk in terms of a unitary colligation transfer function representation. We generalize this to the unit ball of the algebra of multipliers for a…

Functional Analysis · Mathematics 2007-05-23 Michael A. Dritschel , Stefania Marcantognini , Scott McCullough

We investigate the Schwarz lemma and the Schur algorithm for elements in the unit ball of the multiplier algebra of a reproducing kernel Hilbert space on the open unit ball whose kernel satisfies the complete Nevanlinna-Pick property. This…

Functional Analysis · Mathematics 2023-12-05 Daniel Alpay , Tirthankar Bhattacharyya , Abhay Jindal , Poornendu Kumar

we start the study of Schur analysis in the quaternionic setting using the theory of slice hyperholomorphic functions. The novelty of our approach is that slice hyperholomorphic functions allows to write realizations in terms of a suitable…

Functional Analysis · Mathematics 2011-10-13 Daniel Alpay , Fabrizio Colombo , Irene Sabadini

We study several aspects concerning slice regular functions mapping the quaternionic open unit ball into itself. We characterize these functions in terms of their Taylor coefficients at the origin and identify them as contractive…

Complex Variables · Mathematics 2013-08-13 Daniel Alpay , Vladimir Bolotnikov , Fabrizio Colombo , Irene Sabadini

The calculation of inclusive processes that involve the production of many particles is a challenge for lattice QCD, a Euclidean-space method that is far removed from real-time, multiparticle production. A new approach to this problem based…

High Energy Physics - Lattice · Physics 2026-05-19 Sarah Fields , Norman Christ

Nevanlinna-Pick interpolation developed from a topic in classical complex analysis to a useful tool for solving various problems in control theory and electrical engineering. Over the years many extensions of the original problem were…

Functional Analysis · Mathematics 2022-05-30 Sanne ter Horst , Alma van der Merwe

Rational inner functions are a generalization of finite Blaschke products to several variables. In this article we survey a variety of results about rational inner functions related to interpolation, sums of squares formulas, and boundary…

Functional Analysis · Mathematics 2025-02-20 Greg Knese

A boundary Nevanlinna-Pick interpolation problem is posed and solved in the quaternionic setting. Given nonnegative real numbers $\kappa_1, \ldots, \kappa_N$, quaternions $p_1, \ldots, p_N$ all of modulus $1$, so that the $2$-spheres…

Complex Variables · Mathematics 2014-05-27 K. Abu-Ghanem , D. Alpay , F. Colombo , D. P. Kimsey , I. Sabadini

In this note we revive a transformation that was introduced by H. S. Wall and that establishes a one-to-one correspondence between continued fraction representations of Schur, Carath\'eodory, and Nevanlinna functions. This transformation…

Classical Analysis and ODEs · Mathematics 2016-09-29 Maxim Derevyagin

An indefinite generalization of Nudel'man's problem is used in a systematic approach to interpolation theorems for generalized Schur and Nevanlinna functions with interior and boundary data. Besides results on existence criteria for…

Functional Analysis · Mathematics 2007-05-23 D. Alpay , T. Constantinescu , A. Dijksma , J. Rovnyak

A general theory of matrix-spherical functions for dual Hopf algebras and right coideal subalgebras is developed. We establish their existence and define their orthogonality relations. When specialized to Kolb and Letzter's quantum…

Quantum Algebra · Mathematics 2025-12-01 Stein Meereboer , Philip Schlösser

We describe those reproducing kernel Hilbert spaces of holomorphic functions on domains in ${\Bbb C}^d$ for which an analogue of the Nevanlinna-Pick theorem holds, in other words when the existence of a (possibly matrix-valued) function in…

Functional Analysis · Mathematics 2016-10-07 Jim Agler , John E. McCarthy

First, an abstract scheme of constructing biorthogonal rational systems related to some interpolation problems is proposed. We also present a modification of the famous step-by-step process of solving the Nevanlinna-Pick problems for…

Classical Analysis and ODEs · Mathematics 2008-06-28 Maxim S. Derevyagin , Alexei S. Zhedanov

The main purpose of this paper is to present a systemic study of some families of multiple $q$-Euler numbers and polynomials. In particular, by using the $q$-Volkenborn integration on $\Bbb Z_p$, we construct $p$-adic $q$-Euler numbers and…

Number Theory · Mathematics 2007-05-23 Taekyun Kim