English

Complex flows, escape to infinity and a question of Rubel

Complex Variables 2021-05-13 v1

Abstract

Let ff be a transcendental entire function. It was shown in a previous paper that the holomorphic flow z˙=f(z)\dot z = f(z) always has infinitely many trajectories tending to infinity in finite time. It will be proved here that such trajectories are in a certain sense rare, although an example will be given to show that there can be uncountably many. In contrast, for the classical antiholomorphic flow z˙=fˉ(z)\dot z = \bar f(z), such trajectories need not exist at all, although they must if ff belongs to the Eremenko-Lyubich class B\mathcal{B}. It is also shown that for transcendental entire ff in B\mathcal{B} there exists a path tending to infinity on which ff and all its derivatives tend to infinity, thus affirming a conjecture of Rubel for this class.

Keywords

Cite

@article{arxiv.2105.05452,
  title  = {Complex flows, escape to infinity and a question of Rubel},
  author = {J. K. Langley},
  journal= {arXiv preprint arXiv:2105.05452},
  year   = {2021}
}