Bitlyan-Gol'dberg type inequality for entire functions and diagonal maximal term
Abstract
In the article is obtained an analogue of Wiman-Bitlyan-Gol'dberg type inequality for entire $f\colon\mathbb{C}^p\to \mathbb{C}$ from the class $\mathcal{E}^{p}(\lambda)$ of functions represented by gap power series of the form
$$
f(z)=\sum\limits_{k=0}^{+\infty} P_k(z),\quad
z\in\mathbb{C}^p.
$$
Here $P_0(z)\equiv a_{0}\in\mathbb{C},$ $
P_k(z)=\sum_{\|n\|=\lambda_k} a_{n}z^{n}$ is homogeneous
polynomial of degree $\lambda_k\in\mathbb{Z}_+,$ ànd $ 0=\lambda_0<
\lambda_k\uparrow +\infty$\ $(1\leq k\uparrow +\infty ),$
$\lambda=(\lambda_k)$.\ We consider the exhaustion of the
space\ $\mathbb{C}^{p}$\
by the system $(\mathbf{G}_{r})_{r\geq 0}$ of a bounded complete multiple-circular domains $\mathbf{G}_{r}$
with the center at the point $\mathbf{0}=(0,\ldots,0)\in \mathbb{C}^{p}$. Define $M(r,f)=\max\{|f(z)|\colon z\in\overline{G}_r\}$, $\mu(r,f)=\max\{|P_k(z))|\colon z\in\overline{G}_r\}$.
Let $\mathcal{L}$ be the class of positive continuous functions $\psi\colon \mathbb{R}_{+}\to\mathbb{R}_{+}$ such that $\int_{0}^{+\infty}\frac{dx}{\psi(x)}<+\infty$, $n(t)=\sum_{\lambda_k\leq t}1$ counting function of the sequence $(\lambda_k)$ for $t\geq 0$. The following statement is proved:
{\it If a sequence $\lambda=(\lambda_{k})$ satisfy the condition
\begin{equation*}
(\exists p_1\in (0,+\infty))(\exists t_0>0)(\forall t\geq t_0)\colon\quad n(t+\sqrt{\psi(t)})-n(t-\sqrt{\psi(t)})\leq t^{p_1}
\end{equation*}
for some function $\psi\in \mathcal{L}$,
then for every entire function $f\in\mathcal{E}^{p}(\lambda)$, $p\geq 2$ and for any
$\varepsilon>0$ there exist a constant $C=C(\varepsilon, f)>0$ and a set $E=E(\varepsilon, f)\subset [1,
+\infty)$ of finite logarithmic measure such that the inequality
\begin{equation*}
M(r, f)\leq C m(r,
f)(\ln m(r, f))^{p_1}(\ln\ln m(r, f))^{p_1+\varepsilon}
\end{equation*}
holds for all $ r\in[1,
+\infty]\setminus E$.}
The obtained inequality is sharp in general.
At $\lambda_k\equiv k$, $p=2$ we have $p_1=1/2+\varepsilon$ and the Bitlyan-Gol'dberg inequality (1959) it follows. In the case $\lambda_k\equiv k$, $p=2$ we have $p_1=1/2+\varepsilon$ and from obtained statement we get the assertion on the Bitlyan-Gol'dberg inequality (1959), and at $p=1$ about the classical Wiman inequality it follows.
References
Bitlyan I.F., Goldberg A.A. Wiman-Valiron’s theorem for entire functions of several complex variables// Vestn. Leningrad univ. ser. mat., mech. and astr. – 1959. – V.2, No13. – P. 27–41. (in Russian)
O.B. Skaskiv, On the classical Wiman’s inequality for entire Dirichlet series, Visn. Lviv. Univer., ser. mekh.-mat. – 1999. – V.54. – P. 180–182. (in Ukrainian)
M.M. Sheremeta, Wiman-Valiron’s method for entire functions, represented by Dirichlet series, Dokl. USSR Acad. Sci. – 1978. – V.240, No5. – P. 1036–1039. (in Russian)
Skaskiv O.B. Random gap power series and Wiman’s inequality// Mat. Stud. – 2008. – V.30, No1. – P. 101–106. (in Ukrainian)
Valiron G. Functions analytiques. – Paris: Press Univer. de France, 1954.
Wittich H. Neuer Untersuchungen über eindeutige analytische Funktionen. – Berlin-Göttingen-
Heidelberg: Springer-Verlag, 1955.
Kuryliak A.O., Ovchar I.E., Skaskiv O.B. Wiman’s inequality for Laplace integrals// Int. Journal of Math. Analysis. – 2014. – V.8, No8. – P. 381–385.
Schumitsky A. Wiman-Valyron theory for entire functions of several complex variables. – Ph.D. Thesis, Cornell Univ., 1965.
Shumitzky A. A probabilistic approach to the Wiman-Valiron’s theory for entire functions of several complex variables// Complex Variables. – 1989. – V.13. – P. 85–98.
Fenton P.C. Wiman-Valiron theory in two variables// Trans. Amer. Math. Soc. – 1995.– V.347, No11. – P. 4403–4412.
Skaskiv O.B., Trakalo O.M. On classical Wiman’s inequality for entire Dirichlet series// Mat. metods and fys.-mekh. polya. – 2000. – V.43, No3. – P. 34–39. (in Ukrainian)
Zrum O.V., Skaskiv O.B. On Wiman’s inequality for random entire functions of two variables// Mat. Stud. – 2005. – V.23, No2. – P. 149–160. (in Ukrainian)
Skaskiv O.B., Zrum O.V. Wiman-type inequalities for entire functions of two complex variables with rapidly oscillating coefficients// Mat. Metody Phys.-Mekh. Polya. – 2005. – V.48, No4. – P. 78–87. (in
Ukrainian)
Skaskiv O.B., Zrum O.V. Refinement of Fenton’s inequality for entire functions of two complex variables//
Mat. Visn. Nauk. Tov. Im. Shevchenka. – 2006. – V.3. – P. 56–68. (in Ukrainian)
Gopala Krishna J. Generalised inverse and probability techniques and some fundamental growth theorems
in Ck // J. Indian Math. Soc. – 1977. – V.41. – P. 203–219.
Gopala Krishna J., Nagaraja Rao I.H. Generalised inverse and probability techniques and some fundamental growth theorems in Ck // Jour. of the Indian Math. Soc. – 1977. – V.41. – P. 203–219.
O.B. Skaskiv, Random gap power series and Wiman’s inequality// Mat. Stud. – 2008. – V.30, No1. – P. 101–106. (in Ukrainian)
Kuryliak A.O., Skaskiv O.B. Wiman’s type inequalities without exceptional sets for random entire functions of several variables// Mat. Stud. – 2012. – V.38, No1. – P. 35–50.
Skaskiv O. B., Kuryliak A. O. Maximum modulus of entire functions of two variables and arguments of coefficients of double power series// Mat. Stud. – 2011. – V.36, No2. – P. 162–175.
Zrum O.V., Kuryliak A.O., Skaskiv O.B. Levy’s phenomenon for entire functions of several variables// arXiv: 1307.6164v1 [math.CV] 23 Jul 2013. – 14 p.
Kuryliak A.O., Skaskiv O.B., Zrum O.V. Levy’s phenomenon for entire functions of several variables// Ufa Math. J. – 2014. – Т.6, No2. – P. 111–120.
Kuryliak A.O., Shapovalovska L.O., Skaskiv O.B. Wiman’s type inequality for some double power series// Mat. Stud. – 2013. – V.39, No2. – P. 134–141.
Kuryliak A.O., Shapovalovska L.O. Wiman’s type inequality for entire functions of several complex variables with rapidly oscillating coefficients// Mat. Stud. – 2015. – V.43, No1. – P. 16–26. doi: 10.15330/ms.43.1.16-26
Kuryliak A.O., Skaskiv O.B., Shapovalovska L.O. Wiman’s inequality for analityc functions in a bydisc// Visn. Lviv. Univ. – 2014. – Vyp.79. –P. 89–96 (2014) (in Ukrainian)
Kuryliak A.O., Shapovalovska L.O., Skaskiv O.B. Wiman’s type inequality for analytic functions in a polydisc// Ukr. Mat. Zh. – 2016. –V.68, No.1. –P. 78–86 (2016) (in Ukrainian)
Kuryliak A.O., Tsvigun V.L. Wiman’s type inequality for multiple power series in an unbounded cylinder domain// Mat. Stud. – 2018. – V.49, No1. – P. 29–51.
Kuryliak A., Skaskiv O., Skaskiv S. Levy’s phenomenon for analytic functions on a polydisk// European Journal of Mathematics. – 2020. – V.6, No1. – P. 138–152 doi.org/10.1007/s40879-019-00363-2
Panchuk S.I., Skaskiv O.B. Lacunary multiple power series and Wiman’s inequality// International conference dedicated to the 120th anniversary of Stefan Banach (Lviv, 17.09—21.09.2012): Abstract of Reports. – Lviv, 2012. — P. 172–173.
Skaskiv O.B. On certain relations between the maximum modulus and the maximal term of an entire Dirichlet series, Math. Notes. – 1999. – V.66, No2. – P. 223–232. Transl. from Mat. Zametky. – 1999.V.66, No2. – P. 282–292.
Skaskiv O.B., Zrum O.V., On an exeptional set in the Wiman inequalities for entire functions// Mat. Stud. – 2004. – V.21, No1. – P. 13–24. (in Ukrainian)
Skaskiv O.B., Filevych P.V., On the size of an exceptional set in the Wiman theorem, Mat. Stud. – 1999. – V.12, No1. – P. 31–36. (in Ukrainian)
Copyright (c) 2020 A. O. Kuryliak, O. B. Skaskiv, S. I. Panchuk
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Matematychni Studii is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) license.