On the relative growth of Dirichlet series absolutely

Author(s): Myroslav M. Sheremeta1
1Ivan Franko National University of Lviv, Lviv, Ukraine
Copyright © Myroslav M. Sheremeta. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Let \(\Lambda = (\lambda_n)\) be an increasing sequence of non-negative numbers tending to \(+\infty\), with \(\lambda_0 = 0\). We denote by \(S(\Lambda, 0)\) a class of Dirichlet series \(F(s) = \sum_{n=0}^{\infty} f_n \exp\{s \lambda_n\}, \quad s = \sigma + it,\) which have an abscissa of absolute convergence \(\sigma_a = 0\). For \(\sigma < 0\), we define \( M_F(\sigma) = \sup \{|F(\sigma + it)| : t \in \mathbb{R}\}. \) The growth of the function \(F \in S(\Lambda, 0)\) is analyzed in relation to the function \( G(s) = \sum_{n=0}^{\infty} g_n \exp\{s \lambda_n\} \in S(\Lambda, 0), \) via the growth of the function \(1/|M^{-1}_G(M_F(\sigma))|\) as \(\sigma \uparrow 0\). We investigate the connection between this growth and the behavior of the coefficients \(f_n\) and \(g_n\) in terms of generalized orders.