A concept of boundedness of the L-index in joint variables (see in Bandura A. I., Bordulyak M. T., Skaskiv O. B. Sufficient conditions of boundedness of L-index in joint variables, Mat. Stud. 45 (2016), 12–26) is generalized ...

In the present paper we solve the indefinite Stieltjes moment problem MPkκ(s) within the M.G. Krein theory of u-resolvent matrices applied to a Pontryagin space symmetric operator A[0,N] generated by J[0,N]. The u-resolvent ...

In the paper, we study automorphisms of the extensions of groups, finite monogenic semigroups and describe the automorphism groups of extensions of null semigroups, almost null semigroups, right zero semigroups and left ...

The class of γ–generating matrices and its subclasses of regular and singular γ–generating matrices were introduced by D. Z. Arov in [8], where it was shown that every γ-generating matrix admits an essentially unique ...

Assume that Ω is a domain in the complex plane C and A(z) is symmetric 2× 2 matrix function with measurable entries, det A = 1 and such that 1/K|ξ|²≤ 〈A(z)ξ, ξ〉 ≤ K|ξ|², ξ ∊ R², 1 ≤ K < ∞. In particular, for semi-linear ...

In this paper a solution of the one difference equation was investigated.

We consider first-order symmetric system Jy′ −A(t)y = λ∆(t)y with n×n-matrix coefficients defined on an interval [a, b) with the regular endpoint a. It is assumed that the deficiency indices N± of the system satisfies N− ...

We study various Stieltjes integrals as Poisson–Stieltjes, conjugate Poisson–Stieltjes, Schwartz–Stieltjes and Cauchy–Stieltjes and prove theorems on the existence of their finite angular limits a.e. in terms of the ...

В работе предлагается обобщение понятия внутреннего радиуса на случай n-мерного комплексного пространства, что позволяет перенести некоторые результаты, известные в случае комплексной плоскости, на Cⁿ.