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We obtain Schwarz-Pick lemma for $(\alpha, \beta)$-harmonic functions u in the disc, where $\alpha$ and $\beta$ are complex parameters satisfying $\Re \alpha + \Re \beta > -1$. We prove sharp estimate of derivative at the origin for such…

Complex Variables · Mathematics 2023-12-13 Miloš Arsenović , Jelena Gajić

We prove sharp Landau- and Schottky-type theorems for analytic functions which omit the $n$-th roots of unity. The proofs are based on a sharp lower bound for the Poincar\'e metric of the complex plane punctured at the roots of unity.

Complex Variables · Mathematics 2014-05-05 Daniela Kraus , Oliver Roth

We provide a general approach to Lipschitz regularity of solutions for a large class of vector-valued, nonautonomous variational problems exhibiting nonuniform ellipticity. The functionals considered here range amongst those with unbalanced…

Analysis of PDEs · Mathematics 2021-08-02 Cristiana De Filippis , Giuseppe Mingione

For a slice--regular quaternionic function $f,$ the classical exponential function $\exp f$ is not slice--regular in general. An alternative definition of exponential function, the $*$-exponential $\exp_*$, was given: if $f$ is a…

Complex Variables · Mathematics 2024-03-12 Graziano Gentili , Jasna Prezelj , Fabio Vlacci

We study some harmonic properties of slice regular functions in one and several Clifford variables and give explicit formulas of the iterated Laplacian applied to slice regular functions and to their spherical derivative, which are new also…

Complex Variables · Mathematics 2025-03-07 Giulio Binosi

Sectional curvature bounds are of central importance in the study of Riemannian manifolds, both in smooth differential geometry and in the generalized synthetic setting of Alexandrov spaces. Riemannian metrics along with metric spaces of…

Differential Geometry · Mathematics 2026-01-30 Darius Erös , Michael Kunzinger , Argam Ohanyan , Alessio Vardabasso

We obtain a new formula to relate the value of a Schur polynomial with variables $(x_1,\ldots,x_N)$ with values of Schur polynomials at $(1,\ldots,1)$. This allows to study the limit shape of perfect matchings on a square hexagon lattice…

Probability · Mathematics 2021-09-30 Zhongyang Li

In this paper we study the additive splitting associated to the quaternionic Cauchy transform defined by the Cauchy formula of slice hyperholomorphic functions. Moreover, we introduce and study the analogue of the fundamental solution of…

Complex Variables · Mathematics 2019-01-30 Fabrizio Colombo , Samuele Mongodi

Slice analysis is a generalization of the theory of holomorphic functions of one complex variable to quaternions. Among the new phenomena which appear in this context, there is the fact that the convergence domain of…

Complex Variables · Mathematics 2021-01-26 Xinyuan Dou , Guangbin Ren , Irene Sabadini

We extend the classical Titchmarsh theorems to the Fourier transform of two types of H\"older-Lipschitz functions - additive and multiplicative - defined on fundamental domains of lattices in $\mathbb{R}^d$. Our approach is based on…

Functional Analysis · Mathematics 2025-12-24 Arne Hendrickx

We prove and apply two theorems: First, a quantitative, scale-free unique continuation estimate for functions in a spectral subspace of a Schr\"odinger operator on a bounded or unbounded domain, second, a perturbation and lifting estimate…

Spectral Theory · Mathematics 2020-08-18 Ivica Nakić , Matthias Täufer , Martin Tautenhahn , Ivan Veselic , Albrecht Seelmann

In this article, we prove the analogue theorems of Stein-Tomas and Srtichartz on the discrete surface restrictions of Fourier-Hermite transforms associated with the normalized Hermite polynomials and obtain the Strichartz estimate for the…

Classical Analysis and ODEs · Mathematics 2025-03-10 Sunit Ghosh , Jitendriya Swain

We give a complete description of the possible ranges of real Smirnov functions (quotients of two bounded analytic functions on the open unit disk where the denominator is outer and such that the radial boundary values are real almost…

Complex Variables · Mathematics 2017-10-17 Timothy Ferguson , William T. Ross

We prove a theorem which provides a method for constructing points on varieties defined by certain smooth functions. We require that the functions are definable in a definably complete expansion of a real closed field and are locally…

Logic · Mathematics 2014-02-26 G. O. Jones , A. J. Wilkie

In this paper we prove a Schwarz-Pick lemma for bounded complex-valued harmonic functions in the unit ball of R^n.

Complex Variables · Mathematics 2013-03-14 Dai Shaoyu , Pan Yifei

We study in detail the zero set of a regular function of a quaternionic or octonionic variable. By means of a division lemma for convergent power series, we find the exact relation existing between the zeros of two octonionic regular…

Complex Variables · Mathematics 2010-08-26 Riccardo Ghiloni , Alessandro Perotti

In 1994, M. M. Popov [On integrability in F-spaces, Studia Math. no 3, 205-220] showed that the fundamental theorem of calculus fails, in general, for functions mapping from a compact interval of the real line into the lp-spaces for 0<p<1,…

Functional Analysis · Mathematics 2013-08-29 Fernando Albiac , Jose L Ansorena

In the present paper we establish the solvability of the Regularity boundary value problem in domains with (flat and Lipschitz) lower dimensional boundaries for operators whose coefficients exhibit small oscillations analogous to the…

Analysis of PDEs · Mathematics 2022-08-02 Zanbing Dai , Joseph Feneuil , Svitlana Mayboroda

The main technical result of the paper is a Bochner type formula for the sub-laplacian on a quaternionic contact manifold. With the help of this formula we establish a version of Lichnerowicz' theorem giving a lower bound of the eigenvalues…

Differential Geometry · Mathematics 2011-12-06 Srefan Ivanov , Alexander Petkov , Dimiter Vassilev

The theory of slice regular functions of a quaternion variable is applied to the study of orthogonal complex structures on domains \Omega\ of R^4. When \Omega\ is a symmetric slice domain, the twistor transform of such a function is a…

Differential Geometry · Mathematics 2015-07-27 Graziano Gentili , Simon Salamon , Caterina Stoppato