


Vol 53, No 6 (2018)
- Year: 2018
- Articles: 7
- URL: https://journals.rcsi.science/1068-3623/issue/view/14093
Differential and Integral Equations
On a Class of Weakly Hyperbolic Operators
Abstract
The paper considers Cauchy problem in the Gevre type multianisotropic spaces. Necessary and sufficient conditions for unique solvability of this problem are obtained and the properties of operators (polynomials) that are hyperbolic with a specified weight are investigated.



On Compactness of Regular Integral Operators in the Space L1
Abstract
In this paper we obtain a sufficient condition for quite continuity of Fredholm type integral operators in the space L1(a, b). Uniform approximations by operators with degenerate kernels of horizontally striped structures are constructed. A quantitative error estimate is obtained. We point out the possibility of application of the obtained results to second kind integral equations, including convolution equations on a finite interval, equations with polar kernels, one-dimensional equations with potential type kernels, and some transport equations in non-homogeneous layers.



Functional Analysis
Sharp Norm Estimates for Weighted Bergman Projections in the Mixed Norm Spaces
Abstract
In this paper, we show that the norm of the Bergman projection on Lp,q-spaces in the upper half-plane is comparable to csc(π/q). Then we extend this result to a more general class of domains, known as the homogeneous Siegel domains of type II.



Real and Complex Analysis
Almost Everywhere Convergence of Greedy Algorithm with Respect to Vilenkin System
Abstract
In this paper, we prove that for any ε ∈ (0, 1) there exists ameasurable set E ∈ [0, 1) with measure |E| > 1 − ε such that for any function f ∈ L1[0, 1), it is possible to construct a function \(\tilde f \in {L^1}[0,1]\) coinciding with f on E and satisfying \(\int_0^1 {|\tilde f(x) - f(x)|dx < \varepsilon } \), such that both the Fourier series and the greedy algorithm of \(\tilde f\) with respect to a bounded Vilenkin system are almost everywhere convergent on [0, 1).



On Some Subclasses of Delta-Subharmonic Functions of Bounded Type in the Disc
Abstract
The paper gives the delta-subharmonic extension of the part of the factorization theory of M. M. Djrbashian - V. S. Zakaryan, which relates with the descriptive representations of the classes N{ω} of functions meromorphic in the unit disc, contained in Nevanlinna’s class N of functions of bounded type.



Certain Classes of Analytic Functions Related to the Crescent-Shaped Regions
Abstract
In this paper, we study certain classes of analytic functions which satisfy a subordination condition and are associated with the crescent-shaped regions. We first give certain integral representations for the functions belonging to these classes and also present a relevant example. Making use of some known lemmas, we derive sufficient conditions for the functions to be in these classes. Some results on coefficient estimates are also obtained.



Stochastic and Integral Geometry
The Sine Representation of Centrally Symmetric Convex Bodies
Abstract
The problem of the sine representation for the support function of centrally symmetric convex bodies is studied. We describe a subclass of centrally symmetric convex bodies which is dense in the class of centrally symmetric convex bodies. Also, we obtain an inversion formula for the sine-transform.


