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Octonionic analysis is becoming eminent due to the role of octonions in the theory of G2 manifold. In this article, a new slice theory is introduced as a generalization of the holomorphic theory of several complex variables to the…

Complex Variables · Mathematics 2018-12-12 Guangbin Ren , Ting Yang

In this paper we consider Hankel operators on domains with bounded intrinsic geometry. For these domains we characterize the $L^2$-symbols where the associated Hankel operator is compact (respectively bounded) on the space of square…

Complex Variables · Mathematics 2021-06-01 Andrew Zimmer

The purpose of this paper is twofold. One is to enrich from a geometrical point of view the theory of octonionic slice regular functions. We first prove a boundary Schwarz lemma for slice regular self-mappings of the open unit ball of the…

Complex Variables · Mathematics 2016-04-15 Xieping Wang

In this paper, we initiate the study of the geometric function theory for slice starlike functions over quaternions and its subclasses. This allows us to answer negatively some questions about the Bieberbach conjecture, the growth,…

Complex Variables · Mathematics 2025-03-18 Zhenghua Xu , Guangbin Ren

This note deals with the boundedness of the $H^\infty$ functional calculus of Ritt operators $T$ and associated square function estimates. The purpose is to give a shorter, concise and slightly more general approach towards Le~Merdy's…

Functional Analysis · Mathematics 2023-03-07 Bernhard H. Haak

The aim of this work is to study frame theory in quaternionic Hilbert spaces. We provide a characterization of frames in these spaces through the associated operators. Additionally, we examine frames of the form $\{Lu_i\}_{i \in I}$, where…

Functional Analysis · Mathematics 2024-11-07 Najib Khachiaa

This paper addresses particular eigenvalue problems within the context of two quaternionic function theories. More precisely, we study two concrete classes of quaternionic eigenvalue problems, the first one for the slice derivative operator…

Complex Variables · Mathematics 2023-10-16 Rolf Sören Krausshar , Alessandro Perotti

In this paper we provide a general construction of a quaternionic Banach space of slice regular functions from a given Banach space of holomorphic functions, which we call its quaternionic lift. To the best of our knowledge, this…

Functional Analysis · Mathematics 2025-12-09 Nikolaos Chalmoukis , Giulia Sarfatti

We study the Hp-Lq boundedness of certain integral operators of fractional type.

Classical Analysis and ODEs · Mathematics 2017-03-10 Pablo Rocha

In this paper we introduce and study some basic properties of the Fock space (also known as Segal-Bargmann space) in the slice hyperholomorphic setting. We discuss both the case of slice regular functions over quaternions and also the case…

Complex Variables · Mathematics 2014-06-24 Daniel Alpay , Fabrizio Colombo , Irene Sabadini , Guy Salomon

In this paper we prove a new representation formula for slice regular functions, which shows that the value of a slice regular function $f$ at a point $q=x+yI$ can be recovered by the values of $f$ at the points $q+yJ$ and $q+yK$ for any…

Complex Variables · Mathematics 2010-03-30 Fabrizio Colombo , Graziano Gentili , Irene Sabadini , Daniele C. Struppa

The concept of slice regular function over the real algebra $\mathbb{H}$ of quaternions is a generalization of the notion of holomorphic function of a complex variable. Let $\Omega$ be an open subset of $\mathbb{H}$, which intersects…

Complex Variables · Mathematics 2020-11-20 Riccardo Ghiloni

In this paper we extend the $H^\infty$ functional calculus to quaternionic operators and to $n$-tuples of noncommuting operators using the theory of slice hyperholomorphic functions and the associated functional calculus, called…

Functional Analysis · Mathematics 2015-11-25 D. Alpay , F. Colombo , T. Qian , I. Sabadini

In this paper we propose an Almansi-type decomposition for slice regular functions of several quaternionic variables. Our method yields $2^n$ distinct and unique decompositions for any slice function with domain in $\mathbb{H}^n$. Depending…

Complex Variables · Mathematics 2024-11-12 Giulio Binosi

We study the boundedness of certain fractional integral operators from Hp(.) into Lq(.). We also obtain the Hp(.)- Hq(.) boundedness of the Riesz potential.

Classical Analysis and ODEs · Mathematics 2016-06-21 Pablo Rocha , Marta Urciuolo

Two themes drive this article: identifying the structure necessary to formulate quaternionic operator theory and revealing the relation between complex and quaternionic operator theory. The theory of quaternionic right linear operators is…

Spectral Theory · Mathematics 2018-03-29 Jonathan Gantner

Slice regular functions are a generalization of holomorphic functions to the setting of quaternions (and more generally, Clifford algebras). In this paper, we first establish the Bohr inequality for slice starlike functions and slice…

Complex Variables · Mathematics 2025-11-18 Sabir Ahammed , Molla Basir Ahamed , Ming-Sheng Liu

We characterise slice-regularity of functions over a real alternative *-algebra using operators that arise in Dunkl operator theory. We present a unifying perspective on hypercomplex analysis by defining a family of function spaces in the…

Complex Variables · Mathematics 2026-02-03 Giulio Binosi , Alessandro Perotti

We develop an operator-theoretic approach to quaternionic Fock spaces, with emphasis on Carleson measures, Berezin transforms, and Toeplitz operators. We first introduce a global Gaussian $L^p$-framework on $\mathbb H$ for slice functions…

Functional Analysis · Mathematics 2026-03-24 Zhaopeng Lin , Yufeng Lu , Chao Zu

Using the $H^\infty$-functional calculus for quaternionic operators, we show how to generate the fractional powers of some densely defined differential quaternionic operators of order $m\geq 1$, acting on the right linear quaternionic…

Spectral Theory · Mathematics 2021-12-13 Luca Baracco , Fabrizio Colombo , Marco M. Peloso , Stefano Pinton