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In the paper, we prove that the set of discrete shifts of the Riemann zeta-function (ζ(s + 2πia1k), . . ., ζ(s + 2πiark)), k ∈ N, approximating analytic non-vanishing functions f1(s), . . ., fr(s) defined on {s ∈ C : 1/2 < Res < 1} has a positive density in the interval [N,N + M] with M = o(N), N → ∞, with real algebraic numbers a1, . . ., ar linearly independent over Q. A similar result is obtained for shifts of certain absolutely convergent Dirichlet series. [ABSTRACT FROM AUTHOR]

In the paper, we construct an absolutely convergent Dirichlet series which in the mean is close to the periodic Hurwitz zeta-function, and has the universality property on the approximation of a wide class of analytic functions. [ABSTRACT FROM AUTHOR]

In the paper, an universality theorem of discrete type on the approximation of analytic functions by shifts of a special absolutely convergent Dirichlet series is obtained. These series is close in a certain sense to the periodic zeta-function and depends on a parameter. [ABSTRACT FROM AUTHOR]

Let H(D) be the space of analytic functions on the strip D = {σ + it ∈ C : 1/2 < σ < 1}. In this paper, it is proved that there exists a closed non-empty set Fα1,...,αr ⊂ H(D) such that every collection of the functions (f1, . . ., fr) ∈ Fα1,...,αr is approximated by discrete shifts (ζ(s + ikh1, α1), . . ., ζ(s + ikhr, αr)), hj > 0, j = 1, . . ., r, k ∈ N ∪ {0}, of Hurwitz zeta-functions with arbitrary parameters α1, . . ., αr. [ABSTRACT FROM AUTHOR]

It is well known that the Riemann zeta-function is universal in the Voronin sense, i.e., its shifts ζ(s + iт), т ∊ R, approximate a wide class of analytic functions. The universality of ζ(s) is called discrete if т take values from a certain discrete set. In the paper, we obtain a weighted discrete universality theorem for ζ(s) when т takes values from the arithmetic progression fkh : k ∊ Ng with arbitrary fixed h > 0. For this, two types of h are considered. [ABSTRACT FROM AUTHOR]