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In this note we describe some results concerning upper and lower bounds for the Jensen functional. We use several known and new results to shed light on the concepts of superterzatic functions.

Classical Analysis and ODEs · Mathematics 2016-05-13 Flavia-Corina Mitroi-Symeonidis

The theory of quaternionic slice regular functions was introduced in 2006 and successfully developed for about a decade over symmetric slice domains, which appeared to be the natural setting for their study. Some recent articles paved the…

Complex Variables · Mathematics 2021-05-04 Graziano Gentili , Caterina Stoppato

In the present paper we introduce the class of slice-polynomial functions: slice regular functions {defined over the quaternions, outside the real axis,} whose restriction to any complex half-plane is a polynomial. These functions naturally…

Complex Variables · Mathematics 2019-01-03 Amedeo Altavilla , Giulia Sarfatti

According to [5] we define the $*$-exponential of a slice-regular function, which can be seen as a generalization of the complex exponential to quaternions. Explicit formulas for $\exp_*(f)$ are provided, also in terms of suitable sine and…

Complex Variables · Mathematics 2019-01-03 Amedeo Altavilla , Chiara de Fabritiis

This paper is concerned with a class of generalized slice Fueter-regular functions on arbitrary domains in O with local stem functions. Some classical theorems such as the maximum modulus principle will be generalized to our setting. Some…

Complex Variables · Mathematics 2026-05-12 Xinyuan Dou , Guangbin Ren , Zeping Zhu , Ting Yang

We present some new relations between the Cauchy-Riemann operator on the real Clifford algebra $\mathbb R_n$ of signature $(0,n)$ and slice-regular functions on $\mathbb R_n$. The class of slice-regular functions, which comprises all…

Complex Variables · Mathematics 2022-04-26 Alessandro Perotti

Inequalities play an important role in pure and applied mathematics. In particular, Jensen's inequality, one of the most famous inequalities, plays a main role in the study of the existence and uniqueness of initial and boundary value…

Classical Analysis and ODEs · Mathematics 2022-02-09 Yamilet Quintana , José M. Rodríguez , José M. Sigarreta Almira

The theory of slice regular functions of a quaternionic variable on the unit ball of the quaternions was introduced by Gentili and Struppa in 2006 and nowadays it is a well established function theory, especially in view of its applications…

Functional Analysis · Mathematics 2023-06-22 José Oscar González-Cervantes , Juan Bory-Reyes , Irene Sabadini

We construct a counterexample to a well-known extension theorem for slice regular functions, which motivates us to develop a theory of Riemann slice-domains by introducing a new topology on quaternions. By some paths describing axial…

Complex Variables · Mathematics 2019-02-13 Xinyuan Dou , Guangbin Ren

A direct link between a one-loop N-point Feynman diagram and a geometrical representation based on the N-dimensional simplex is established by relating the Feynman parametric representations to the integrals over contents of…

High Energy Physics - Theory · Physics 2008-11-26 A. I. Davydychev , R. Delbourgo

This work proposes a unified theory of regularity in one hypercomplex variable: the theory of $T$-regular functions. In the special case of quaternion-valued functions of one quaternionic variable, this unified theory comprises…

Complex Variables · Mathematics 2026-04-10 Riccardo Ghiloni , Caterina Stoppato

In this paper we prove a quaternionic positive real lemma as well as its generalized version, in case the associated kernel has negative squares for slice hyperholomorphic functions. We consider the case of functions with positive real part…

Complex Variables · Mathematics 2018-10-16 D. Alpay , F. Colombo , I. Lewkowicz , I. Sabadini

We introduce a polynomial zeta function $\zeta^{(p)}_{P_n}$, related to certain problems of mathematical physics, and compute its value and the value of its first derivative at the origin $s=0$, by means of a very simple technique. As an…

Mathematical Physics · Physics 2009-02-19 Sergio L. Cacciatori

We employ tools from complex analysis to construct the $*$-logarithm of a quaternionic slice regular function. Our approach enables us to achieve three main objectives: we compute the monodromy associated with the $*$-exponential; we…

Complex Variables · Mathematics 2023-10-03 Amedeo Altavilla , Samuele Mongodi

We introduce a non-commutative resultant, for slice regular polynomials in two quaternionic variables, defined in terms of a suitable Dieudonn\'e determinant.We use this tool to investigate the existence of common zeros of slice regular…

Complex Variables · Mathematics 2024-03-27 Anna Gori , Giulia Sarfatti , Fabio Vlacci

The celebrated 100-year old Phragmen-Lindelof principle is a far reaching extension of the maximum modulus theorem for holomorphic functions of one complex variable. In some recent papers there has been a resurgence of interest in…

Complex Variables · Mathematics 2022-09-07 G. Gentili , C. Stoppato , D. C. Struppa

We give a closed formula for the Conway function of a splice in terms of the Conway function of its splice components. As corollaries, we refine and generalize results of Seifert, Torres, and Sumners-Woods.

Geometric Topology · Mathematics 2012-08-09 David Cimasoni

In this paper we improve results related to Normalized Jensen Functional for convex functions and Uniformly Convex Functions.

Functional Analysis · Mathematics 2024-05-27 Shoshana Abramovich

In this paper, we prove that slice polyanalytic functions on quaternions can be considered as solutions of a power of some special global operator with nonconstant coefficients as it happens in the case of slice hyperholomorphic functions.…

Complex Variables · Mathematics 2021-01-06 Daniel Alpay , Kamal Diki , Irene Sabadini

In the literature on slice analysis in the hypercomplex setting, there are two main approaches to define slice regular functions in one variable: one consists in requiring that the restriction to any complex plane is holomorphic (with the…

Complex Variables · Mathematics 2024-06-28 Xinyuan Dou , Guangbin Ren , Irene Sabadini , Ting Yang