Universally Starlike and Pick Functions

Bakan, Andrew; Ruscheweyh, Stephan; Salinas, Luis

Keywords: harmonic functions, pick functions, Starlike, Boundary behavior, H_p -spaces

Abstract

In this note we prove that every φ ∈ U(Λ) is universally starlike, i.e., φ maps every circular domain in Λ containing the origin one-to-one onto a starlike domain. Furthermore, we show that every non-constant function f ∈ P log belongs to the Hardy space H p on the upper half-plane for some constant p = p(f ) > 1, unless f is proportional to some function (a−z) −θ with a ∈ R and 0 < θ ≤ 1. Finally we derive a necessary and sufficient condition on a real-valued function v for which there exists f ∈ P log such that v(x) = lim ε↓0 lim f (x + iε) for almost all x ∈ R.

Más información

Título de la Revista: JOURNAL D ANALYSE MATHEMATIQUE
Editorial: Springer Verlag
Fecha de publicación: 2020
Idioma: English
Financiamiento/Sponsor: FONDECYT; UTFSM; CCTVal
Notas: ISI; SCOPUS