On the Marcinkiewicz-Fejér means of double Fourier series with respect to the Walsh-Kaczmarz system

2009 ◽  
Vol 46 (3) ◽  
pp. 399-421 ◽  
Author(s):  
György Gát ◽  
Ushangi Goginava ◽  
Károly Nagy

The main aim of this paper is to prove that the maximal operator of Marcinkiewicz-Fejér means of double Fourier series with respect to the Walsh-Kaczmarz system is bounded from the dyadic Hardy-Lorentz space Hpq into Lorentz space Lpq for every p > 2/3 and 0 < q ≦ ∞. As a consequence, we obtain the a.e. convergence of Marcinkiewicz-Fejér means of double Fourier series with respect to the Walsh-Kaczmarz system. That is, σn ( f, x1 , x2 ) → ( x1 , x2 ) a.e. as n → ∞.

2007 ◽  
Vol 44 (1) ◽  
pp. 97-115
Author(s):  
Ushangi Goginava

The boundedness of the Marcinkiewicz maximal operator for double Vilenkin-Fourier series from the martingale Hardy-Lorentz space Hp,q into the Lorentz space Lp,q is studied.


2008 ◽  
Vol 45 (3) ◽  
pp. 321-331
Author(s):  
István Blahota ◽  
Ushangi Goginava

In this paper we prove that the maximal operator of the Marcinkiewicz-Fejér means of the 2-dimensional Vilenkin-Fourier series is not bounded from the Hardy space H2/3 ( G2 ) to the space L2/3 ( G2 ).


2010 ◽  
Vol 8 (2) ◽  
pp. 181-200
Author(s):  
Ushangi Goginava ◽  
Károly Nagy

The main aim of this paper is to prove that there exists a martingalef∈H1/2such that the maximal Fejér operator with respect to Walsh-Kaczmarz system does not belong to the spaceL1/2. For the two-dimensional case, we prove that there exists a martingalef∈H1/2□(f∈H1/2)such that the restricted (unrestricted) maximal operator of Fejér means of two-dimensional Walsh-Kaczmarz-Fourier series does not belong to the space weak-L1/2.


2011 ◽  
Vol 60 (2) ◽  
pp. 137-148
Author(s):  
Igor Korotyeyev ◽  
Beata Zięba

Steady-state modelling method for matrix-reactance frequency converter with boost topologyThis paper presents a method intended for calculation of steady-state processes in AC/AC three-phase converters that are described by nonstationary periodical differential equations. The method is based on the extension of nonstationary differential equations and the use of Galerkin's method. The results of calculations are presented in the form of a double Fourier series. As an example, a three-phase matrix-reactance frequency converter (MRFC) with boost topology is considered and the results of computation are compared with a numerical method.


2018 ◽  
pp. 1
Author(s):  
Amira Ali Een Faied

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