Перейти до основного вмісту
On the growth of the maximum modulus of Dirichlet series
Sheremeta Myroslav 1 , Trukhan Yuriy Stepanovych 1
1 Department of theory of functions and functional analysis, Ivan Franko National University of Lviv, Lviv, 79007, Ukraine
Keywords: Dirichlet series, maximum modulus, generalized order
Abstract

For the Dirichlet series F(s) = ∑1 n=0 fn exp{sλn} with nonnegative increasing +∞ exponents λn and abscissa of absolute convergence σa ∈ (−∞; +∞], the connection between the growth on (−∞; σa) of the maximum of the module M(σ; F) = sup{|F(σ + it)| : t ∈ R} and the behavior of the coefficients fn is studied. For this purpose, L denotes the class of continuous increasing up to +∞ on (x0; +∞) functions α. The membership of α in the class L0 means that α ∈ L and α((1 + o(1))x) = (1 + o(1))α(x)
as x → +∞, and α ∈ Lsi if α ∈ L and α(cx) = (1 + o(1))α(x) as x → +∞. For entire Dirichlet series (σa = +∞), for example, it is proved that if α ∈ L, β ∈ L0, then
lim
σ!+1
(exp{α(ln M(β−1(β(σ) + ln q); F))} − p exp{α(ln M(σ; F))}) = +∞ for such p >
1 and q > 1 that lim
n!1
α(λn)=β (λ− n 1 ln (1=|fn|)) > ln p= ln q. If α ∈ Lsi, β ∈ L0,
dβ−1(cα(x))
d ln x = O(1) as x → +∞ and ln n = o(λnβ−1(cα(λn))) as n → ∞ for each
c ∈ (0; +∞), α(λn+1) ∼ α(λn) as n → ∞ and ln |fn| − ln |fn+1|
λn+1 − λn ↗ +∞ for n0 ≤ n → ∞, then
lim
σ!+1
(exp{α(ln M(β−1(β(σ) + ln q); F))} − p exp{α(ln M(σ; F))}) = −∞ for such p > 1
i q > 1, which lim
n!1
α(λn)=β (λ− n 1 ln (1=|fn|)) < ln p= ln q.Similar results were obtained for Dirichlet series absolutely convergent in the half-plane {s :
Res < 0}. For example, it was proved that if σa = 0, β ∈ Lsi, α(ex) ∈ Lsi and α(x) = o(β(x)) as
x → +∞, then
lim
σ"0 (exp {α (ln M (−β−1(β(1=|1σ|) + ln q); F))} − p exp{α(ln M(σ; F))}) = +∞
for such p > 1 and q > 1 that lim
n!1
α(λn)
β(λn= ln+ |fn|) > ln p= ln q.

References

[1] Boychuk V.S. On the growth of Dirichlet series absolutely convergent in a half-plane. Matem. sbornik. Naukova dumka, Kyiv, 1976, 238-240. (in Russian)
[2] Gaisin A. M. A bound for the growth in a half-strip of a function represented by a Dirichlet series. Math. sbornik. 1982, 117(159):(3), 412-424. (in Russian)
[3] Gal’ Yu.M., Sheremeta M.M. On the growth of analytic fuctions in a half-plane given by Dirichlet series. Doklady AN USSR, Ser. A. 1978, no. 12, 1064-1067. (in Russian)
[4] Gal’ Yu.M. On the growth of analytic functions given by Dirichlet series absolute convergent in a half-plane. Drohobych, 1980. Dep. in VINITI, no. 4080-80 Dep. (in Russian)
[5] Goodstein R.L. Complex functions. New York, 1965.
[6] Mulyava O.M., Sheremeta M.M. A remark to the growth of positive functions and its application to Dirichlet series. Mat. Stud. 2015, 44(2), 161-170. doi:10.15330/ms.44.2.161-170
[7] Pyanylo Ya.D., Sheremeta M.M. On the growth of entire fuctions given by Dirichlet series. Izv. Vyssh. Uchebn. Zaved. Mat. 1975, no. 10, 91-93. (in Russian)
[8] Sheremeta M.M. Entire Dirichlet series. ISDO, Kyiv, 1993. (in Ukrainian)
[9] Singh S.K. On the maximum modulus and the means of an entire function. Matem. Vesnik. 1976, 13(28), 211-213.

Cite
ACS Style
Sheremeta, M.; Trukhan, Y.S. On the growth of the maximum modulus of Dirichlet series. Bukovinian Mathematical Journal. 2024, 12 https://doi.org/https://doi.org/10.31861/bmj2024.01.04
AMA Style
Sheremeta M, Trukhan YS. On the growth of the maximum modulus of Dirichlet series. Bukovinian Mathematical Journal. 2024; 12(1). https://doi.org/https://doi.org/10.31861/bmj2024.01.04
Chicago/Turabian Style
Myroslav Sheremeta, Yuriy Stepanovych Trukhan. 2024. "On the growth of the maximum modulus of Dirichlet series". Bukovinian Mathematical Journal. 12 no. 1. https://doi.org/https://doi.org/10.31861/bmj2024.01.04
Export
We use own, third-party cookies, and localStorage files to analyze web traffic and page activities. Privacy Policy Settings