Математика и физика. Mathematics & Physics. 2021 14 (3)
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Limits of Risks Ratios of Shrinkage Estimators under the Balanced Loss Function
(Сибирский федеральный университет. Siberian Federal University, 2021-04)In this paper we study the estimation of a multivariate normal mean under the balanced loss function. We present here a class of shrinkage estimators which generalizes the James-Stein estimator and we are interested to ... -
Removable Singularities of Separately Harmonic Functions
(Сибирский федеральный университет. Siberian Federal University, 2021-04)Removable singularities of separately harmonic functions are considered. More precisely, we prove harmonic continuation property of a separately harmonic function u(x, y) in D \ S to the domain D, when D ⊂ Rn(x) × Rm(y), ... -
Uniqueness and Stability Results for Caputo Fractional Volterra-Fredholm Integro-Differential Equations
(Сибирский федеральный университет. Siberian Federal University, 2021-04)In this paper, we established some new results concerning the uniqueness and Ulam’s stability results of the solutions of iterative nonlinear Volterra-Fredholm integro-differential equations subject to the boundary ... -
Sharply 3-transitive Groups with Finite Element
(Сибирский федеральный университет. Siberian Federal University, 2021-04)In this paper we study sharply 3-transitive groups. The local finiteness of sharply triply transitive permutation groups of characteristic p > 3 containing a finite element of order p is proved. Keywords: group, sharply ... -
Rheological Properties of PVDF Solutions
(Сибирский федеральный университет. Siberian Federal University, 2021-04)The rheological properties of polyvinylidene fluoride (PVDF) solutions in Nmethylpyrrolidone were studied using the rheometric method. It was shown that the viscosity of polymer solutions decreases non-linearly with ... -
Effective Acoustic Equations for a Layered Material Described by the Fractional Kelvin-Voigt Model
(Сибирский федеральный университет. Siberian Federal University, 2021-04)The paper is devoted to the construction of effective acoustic equations for a two-phase layered viscoelastic material described by the Kelvin–Voigt model with fractional time derivatives. For this purpose, the theory ... -
A Note on the Conjugacy Between Two Critical Circle Maps
(Сибирский федеральный университет. Siberian Federal University, 2021-04)We study a conjugacy between two critical circle homeomorphisms with irrational rotation number. Let fi, i = 1, 2 be a C3 circle homeomorphisms with critical point x(i) cr of the order 2mi + 1. We prove that if 2m1 + 1 ... -
The Time-fractional Airy Equation on the Metric Graph
(Сибирский федеральный университет. Siberian Federal University, 2021-04)Initial boundary value problem for the time-fractional Airy equation on a graph with finite bonds is considered in the paper. Properties of potentials for this equation are studied. Using these properties the solutions ... -
Analytic Continuation of Diagonals of Laurent Series for Rational Functions
(Сибирский федеральный университет. Siberian Federal University, 2021-04)We describe branch points of complete q-diagonals of Laurent series for rational functions in several complex variables in terms of the logarithmic Gauss mapping. The sufficient condition of non-algebraicity of such a ... -
Delta-extremal Functions in Cn
(Сибирский федеральный университет. Siberian Federal University, 2021-04)The article is devoted to properties of a weighted Green function. We study the (δ, ψ)- extremal Green function V ∗ δ (z,K, ψ) defined by the class Lδ = { u(z) ∈ psh(Cn) : u(z) 6 Cu + δ ln+ |z|, z ∈ Cn} , δ > 0. We ... -
On Transcendental Systems of Equations
(Сибирский федеральный университет. Siberian Federal University, 2021-04)Several types of transcendental systems of equations are considered: the simplest ones, special, and general. Since the number of roots of such systems, as a rule, is infinite, it is necessary to study power sums of the ... -
Estimating the Mean of Heavy-tailed Distribution under Random Truncation
(Сибирский федеральный университет. Siberian Federal University, 2021-04)Inspired by L.Peng’s work on estimating the mean of heavy-tailed distribution in the case of completed data. we propose an alternative estimator and study its asymptotic normality when it comes to the right truncated ...