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Vol 53, No 6 (2018)

Differential and Integral Equations

On a Class of Weakly Hyperbolic Operators

Margaryan V.N., Ghazaryan H.G.

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.

Journal of Contemporary Mathematical Analysis (Armenian Academy of Sciences). 2018;53(6):307-316
pages 307-316 views

On Compactness of Regular Integral Operators in the Space L1

Yengibaryan B.N., Yengibaryan N.B.

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.

Journal of Contemporary Mathematical Analysis (Armenian Academy of Sciences). 2018;53(6):317-320
pages 317-320 views

Functional Analysis

Sharp Norm Estimates for Weighted Bergman Projections in the Mixed Norm Spaces

Gonessa J.

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.

Journal of Contemporary Mathematical Analysis (Armenian Academy of Sciences). 2018;53(6):321-330
pages 321-330 views

Real and Complex Analysis

Almost Everywhere Convergence of Greedy Algorithm with Respect to Vilenkin System

Grigoryan M.G., Sargsyan S.A.

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 fL1[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).

Journal of Contemporary Mathematical Analysis (Armenian Academy of Sciences). 2018;53(6):331-345
pages 331-345 views

On Some Subclasses of Delta-Subharmonic Functions of Bounded Type in the Disc

Restrepo J.E.

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.

Journal of Contemporary Mathematical Analysis (Armenian Academy of Sciences). 2018;53(6):346-354
pages 346-354 views

Certain Classes of Analytic Functions Related to the Crescent-Shaped Regions

Raina R.K., Sharma P., Sokół J.

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.

Journal of Contemporary Mathematical Analysis (Armenian Academy of Sciences). 2018;53(6):355-362
pages 355-362 views

Stochastic and Integral Geometry

The Sine Representation of Centrally Symmetric Convex Bodies

Aramyan R.H.

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.

Journal of Contemporary Mathematical Analysis (Armenian Academy of Sciences). 2018;53(6):363-368
pages 363-368 views