Wiman's type inequality in the unit ball and the diagonal maximal term

Authors

  • Vitaliy Basovskyi Ivan Franko National University of Lviv, Lviv, Ukraine
  • Andriy Bodnarchuk Ivan Franko National University of Lviv, Lviv, Ukraine
  • Oleh Skaskiv Ivan Franko National University of Lviv
  • Oksana Trusevych Lviv State University of Life Safety

DOI:

https://doi.org/10.31471/2304-7399-2026-22(83)-9-17

Keywords:

analytic function of several complex variables, diagonal maximal term, homogeneous polynomial

Abstract

Let $\mathbb{C}^{p}$ be the $p$-dimensional complex vector space  $(p\geq 1)$, $\|n\|=n_1+\cdots +n_p$, $|z|=\sqrt{|z_1|^2+\ldots+|z_n|^2}$ for $n=(n_1,\ldots,n_p)\in\mathbb{Z}_{+}^{p}$ and $z=(z_1,\ldots , z_p)\in\mathbb{C}^{p}$,\ $\mathbb{R}_{+}= [0, +\infty)$. In the paper we consider the class of analytic functions $f$, represented in the unit ball $\mathbb{B}_p=\{z\in\mathbb{C}^p\colon |z|<1\}$ by power series of the form $f(z)=\sum\limits_{k=0}^{+\infty} P_k(z)$; here $P_0(z)\equiv a_{0}\in\mathbb{C},$ $P_k(z)$ is a homogeneous polynomial of degree $k\in\mathbb{Z}_+$.  We denote $M_f(r)=\max\{|f(z)|\colon |z|=r\}$ and $m(r,f)=\max\{|P_k(z)|\colon k\geq 0\}$, the maximum  modulus and maximal term of series, respectively; $r\in [0, 1)$. In particular, the following statements are proved: $1^0.$\ For every analytic function $f\in\mathcal{A}^{p}$, $p\geq 2$ and for any $\varepsilon>0$ there exists a set $E=E(\varepsilon, f)\subset (0,1)$ of finite logarithmic measure such that  the inequality $M(r, f)\leq \frac{m(r, f)}{(1-r)^{1+\varepsilon}}\Big(\ln\Big(\frac{m(r, f)}{1-r}\Big)\Big)^{1/2+\varepsilon}$ holds for all $ r\in (0, 1)\setminus E$.   $2^0.$  Let $h$ be a continuous positive increasing to $+\infty$ on $[0;1)$ functions such that   $\int^1_{0} h(r) d r =+\infty.$  If the function $f\in\mathcal{A}^p$ is unbounded, then  there exists a set $E_1:=E(f,h)\subset(0,1)$ such that $\ln M(r,f)\leq (1+o(1))\ln\big(h(r)m(r,f)\big)$\ $(r\to 1-0,\ r\in (0,1)\setminus E_1)$, and $h$-${\rm meas\ }E_1=\int_{E_1\cap(0,1)}h(r)dr < +\infty$.

References

1. I.F. Bitlyan, A.A. Goldberg, Wiman-Valiron’s theorem for entire functions of several complex variables, Vestn. Leningrad univ. ser. mat., mech. and astr. 2 (13) (1959), 27–41. (in Russian)

2. A.O. Kuryliak, O.B. Skaskiv, S.I. Panchuk, Bitlyan-Gol’dberg type inequality for entire functions and diagonal maximal term, Mat. Stud., 54 (2) (2020), 135–145. https://doi.org/10.30970/ms.54.2.135-145

3. O. Skaskiv, A. Kuryliak, Wiman’s type inequality for analytic and entire functions and h-measure of an exceptional sets, Carpathian Math. Publ., 12 (2) (2020), 492–498. https://doi.org/10.15330/cmp.12.2.492-498

4. Skaskiv O.B. On certain relations between the maximum modulus and the maximal term of an entire Dirichlet series, Math. Notes., 66 (1999), no. 2, 223–232. https://doi.org/10.1007/BF02674881

5. I.Ye. Ovchar, O.B. Skaskiv, On the estimates of the Laplace integrals on the small parameter, Carpathian Math. Publ., 3 (1) (2011), 106–111. (in Ukrainian) https://journals.pnu.edu.ua/index.php/cmp/article/view/3960/4570

6. A.O. Kuryliak, I.E. Ovchar, O.B. Skaskiv, Wiman’s inequality for Laplace integrals, Int. Journal of Math. Analysis, 8 (8) (2014), 381–385. https://doi.org/10.12988/ijma.2014.4232

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Published

2026-04-24

How to Cite

Basovskyi, V., Bodnarchuk, A., Skaskiv, O., & Trusevych, O. (2026). Wiman’s type inequality in the unit ball and the diagonal maximal term. PRECARPATHIAN BULLETIN OF THE SHEVCHENKO SCIENTIFIC SOCIETY. Number, (22(83), 9–17. https://doi.org/10.31471/2304-7399-2026-22(83)-9-17

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