English

Abel universal functions: boundary behaviour and Taylor polynomials

Complex Variables 2023-10-10 v1

Abstract

A holomorphic function ff on the unit disc D\mathbb{D} belongs to the class UA(D)\mathcal{U}_A(\mathbb{D}) of Abel universal functions if the family {fr:0r<1}\{f_r: 0\leq r<1\} of its dilates fr(z):=f(rz)f_r(z):=f(rz) is dense in the space of continuous functions on KK, for any proper compact subset KK of the unit circle. It has been recently shown that UA(D)\mathcal{U}_A(\mathbb{D}) is a dense GδG_{\delta} subset of the space of holomorphic functions on D\mathbb{D} endowed with the topology of local uniform convergence. In this paper, we develop further the theory of universal radial approximation by investigating the boundary behaviour of functions in UA(D)\mathcal{U}_A(\mathbb{D}) (local growth, existence of Picard points and asymptotic values) and the convergence properties of their Taylor polynomials outside D\mathbb{D}.

Keywords

Cite

@article{arxiv.2310.05611,
  title  = {Abel universal functions: boundary behaviour and Taylor polynomials},
  author = {Stéphane Charpentier and Myrto Manolaki and Konstantinos Maronikolakis},
  journal= {arXiv preprint arXiv:2310.05611},
  year   = {2023}
}
R2 v1 2026-06-28T12:44:30.648Z