Properties of power series of analytic in a bidisc functions of bounded $\mathbf{L}$-index in joint variables

Abstract

We generalized some criteria of boundedness of $\mathbf{L}$-index in joint variables for analytic in a bidisc functions, where $\mathbf{L}(z)=(l_1(z_1,z_2),$ $l_{2}(z_1,z_2)),$ $l_j:\mathbb{D}^2\to \mathbb{R}_+$ is a continuous function, $j\in\{1,2\},$ $\mathbb{D}^2$ is a bidisc $\{(z_1,z_2)\in\mathbb{C}^2: |z_1|<1,|z_2|<1\}.$ We obtained propositions, which describe a behaviour of power series expansion on a skeleton of a bidisc. The power series expansion is estimated by a dominating homogeneous polynomial with a degree that does not exceed some number, depending only from radii of a bidisc. Replacing universal quantifier by existential quantifier for radii of a bidisc, we also proved sufficient conditions of boundedness of $\mathbf{L}$-index in joint variables for analytic functions, which are weaker than necessary conditions.

Authors and Affiliations

A. Bandura, N. Petrechko

Keywords

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  • EP ID EP324739
  • DOI 10.15330/cmp.9.1.6-12
  • Views 77
  • Downloads 0

How To Cite

A. Bandura, N. Petrechko (2017). Properties of power series of analytic in a bidisc functions of bounded $\mathbf{L}$-index in joint variables. Карпатські математичні публікації, 9(1), 6-12. https://europub.co.uk/articles/-A-324739