Title Joint discrete approximation by the Riemann and Hurwitz zeta functions in short intervals
Authors Laurinčikas, Antanas ; Šiaučiūnas, Darius
DOI 10.3390/sym17101662
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Is Part of Symmetry.. Basel : MDPI. 2025, vol. 17, iss. 10, art. no. 1662, p. [1-22].. ISSN 2073-8994
Keywords [eng] approximation of analytic functions ; Hurwitz zeta function ; Riemann zeta function ; universality ; weak convergence of probability measures
Abstract [eng] In this paper, we prove the theorems on the simultaneous approximation of a pair of analytic functions by discrete shifts (𝜁(𝑠+π‘–π‘˜β„Ž1),𝜁(𝑠+π‘–π‘˜β„Ž2,𝛼)), β„Ž1>0, β„Ž2>0 of the Riemann zeta function 𝜁(𝑠) and Hurwitz zeta function 𝜁(𝑠,𝛼). The lower density and density of the above approximating shifts are considered in short intervals [𝑁,𝑁+𝑀] as π‘β†’βˆž with 𝑀=π‘œ(𝑁). If the set {(β„Ž1log𝑝:π‘βˆˆβ„™),(β„Ž2log(π‘š+𝛼):π‘šβˆˆβ„•0),2πœ‹} is linearly independent over β„š, the class of approximated pairs is explicitly given. If 𝛼 and β„Ž1, β„Ž2 are arbitrary, then it is known that the set of approximated pairs is a certain non-empty closed subset of ℍ2(Ξ”), where ℍ(Ξ”) is the space of analytic functions on the strip Ξ”={π‘ βˆˆβ„‚:1/2<Re𝑠<1}. For the proof, limit theorems on weakly convergent probability measures in the space 𝐻2(Ξ”) are applied.
Published Basel : MDPI
Type Journal article
Language English
Publication date 2025
CC license CC license description