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JOURNALS // Matematicheskie Zametki // Archive

Mat. Zametki, 2025 Volume 118, Issue 6, Pages 951–956 (Mi mzm14565)

On common algebraic points of a pair of different derivatives of finite-order meromorphic functions

A. Ya. Yanchenko

National Research University "Moscow Power Engineering Institute"

Abstract: Given nonnegative integers $t<s$, pairs ($f^{(t)}(z)$, $f^{(s)}(z)$) of derivatives of finite-order meromorphic functions $f(z)$ for which $f^{(t)}(z)$ is neither a rational function, a rational function of an exponential $e^{\alpha z}$, nor an elliptic function are considered. For positive integers $n$ and $H$ and a positive number $R$, let $B(n,H,R)$ be the set of points $z$ in the disk $|z|\le R$ for which $f^{(t)}(z)$ and $f^{(s)}(z)$ are algebraic numbers of degree at most $n$ and height at most $H$ (and, moreover, $|f^{(t)}(z)|$ and $|f^{(s)}(z)|$ are not very large). An upper bound for the number of points in $B(n,H,R)$ is obtained for almost all, in a certain sense, $(n,H,R)$.

Keywords: meromorphic function, integer-valued function, algebraic value, pair of derivatives.

UDC: 517.53+511.2

MSC: 11J81

Received: 14.11.2024
Revised: 10.07.2025
Accepted: 12.07.2025

DOI: 10.4213/mzm14565


 English version:
Mathematical Notes, 2025, 118:6, 1329–1333


© Steklov Math. Inst. of RAS, 2026