Year: 2026
Type: preprint
Abstract: We give a negative answer to the second question of Erdős Problem #1117: can the number $ν_f(r)$ of maximum-modulus points of a nonzero, non-monomial entire function on $|z|=r$ tend to infinity as $r\to\infty$? Write $f(z)=z^m g(z)$ with $g(0)\ne0$, and let $k$ be the first positive exponent with a nonzero coefficient in the Taylor expansion of $g$. We prove that $\{r>0:ν_f(r)>2k\}$ is locally finite in $(0,\infty)$, and that the constant $2k$ is sharp. In particular, $\liminf_{r\to\infty}ν_f(r)\le2k<\infty$, without a growth assumption. The proof combines finite local parametrizations of a logarithmic-derivative correspondence with analytic continuation and a local description of stationary points.
Source: arXiv (Cornell University)
Author: Li, Yunpeng
Institution: Chinese University of Hong Kong, Shenzhen
Language: English
Subfield: Applied Mathematics
Field: Mathematics
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7221752425