Аннотация:
We consider some generalizations of Fenton theorem for the entire functions represented by lacunary power series.
Let $f(z)=\sum_{k=0}^{+\infty}f_kz^{n_k}$, where $(n_k)$ is a strictly
increasing sequence of non-negative integers. We denote by
\begin{align*}
&M_f(r)=\max\{|f(z)|\colon |z|=r\},
\\
&m_f(r)=\min\{|f(z)|\colon |z|=r\},
\\
&
\mu_f(r)=\max\{|f_k|r^{n_k}\colon k\geq 0\}
\end{align*}
the maximum modulus,
the minimum modulus and the maximum term of $f,$ respectively.
Let $h(r)$ be a positive continuous function
increasing to infinity on $[1,+\infty)$ with a non-decreasing
derivative. For a measurable set $E\subset [1,+\infty)$ we introduce
$h-\mathrm{meas}\,(E)=\int_{E}\frac{dh(r)}{r}.$
In this paper we establish
conditions guaranteeing that the relations
$$
M_f(r)=(1+o(1)) m_f(r),\quad M_f(r)=(1+o(1))\mu_f(r)
$$
are true as $r\to+\infty$ outside some exceptional set $E$ such that $h-\mathrm{meas}\,(E)<+\infty$. For some subclasses we obtain necessary and sufficient conditions. We also provide similar
results for entire Dirichlet series.
Ключевые слова:lacunary power series, minimum modulus, maximum modulus, maximal term, entire Dirichlet series, exceptional set, $h$-measure.