Multipliers of convergence in norm of series with respect to multiplicative systems

We prove analogs of the Telyakovskii-Pochuev criteria for multipliers of uniform convergence and of convergence in the integral metric for multiplicative systems with bounded generating sequence.     

Fourier transforms in generalized Lipschitz classes

We obtain sufficient conditions for the Fourier transform of a function f ∈ L ₁(?) to belong to generalized Lipschitz classes defined by the modulus of smoothness of order m. The sharpness of these conditions is established in the cases when f(t) ≥ 0 on ? or tf (t) ≥ 0 on ?.     

Generalized fractional integrals in <Emphasis Type="Italic">p</Emphasis>-adic morrey and Herz spaces

For Riesz potential I ^β (f) on p-adic linear space Q _p ⁿ and its modification \(\widetilde{I^\beta }(f)\) we give sufficient conditions of their boundedness from radialMorrey space to anotherMorrey or Campanato space. Also we study the boundedness of modified Riesz potential \(\widetilde{I^\beta }(f)\) from Herz space to special Campanato spaces.     

Generalization of the multiplicative Fourier transform and its properties

We consider a new class of functions on the semiaxis for which the multiplicative Fourier transform can be defined. We prove equalities of Parseval type, an inversion formula and a condition for the validity of representation in the form of the multiplicative Fourier transform.     

Weighted Integrability of Multiple Multiplicative Fourier Transforms

Mathematical Notes - Sufficient conditions for the weighted integrability of multiple multiplicative Fourier transforms of Bernstein–Szasz type involving integral moduli of continuity and of...     

Hausdorff operators on p-adic linear spaces and their properties in Hardy, BMO, and Hölder spaces

Sufficient conditions for the boundedness of p-adic matrix operators in Hardy, Hölder and BMO spaces are obtained. These conditions are expressed in terms of the determinant of the matrix and its norm in a p-adic linear space.     

Generalized <Emphasis Type="Italic">p</Emphasis>-Adic Fourier Transform and Estimates of Integral Modulus of Continuity in Terms of This Transform

We consider a new class of functions on the p-adic linear space ? _p ⁿ for which a Fourier transform can be defined.We prove equalities of Parseval type, an inversion formula and a sufficient condition for a function to be represented as this Fourier transform. Also we give a sharp estimate of the L²(? _p ⁿ ) modulus of continuity in terms of Fourier transform generalizing the result of S. S. Platonov in the case n = 1. Finally we prove a generalization of this result and its converse for L^q(? _p ⁿ ) with appropriate q.     

Convergence of series of Fourier coefficients for multiplicative convolutions

We study the convergence of series of the Fourier-Vilenkin coefficients of functions represented as multiplicative convolutions. In the trigonometric case similar results are obtained by C. Onneweer, M. Izumi, and S. Izumi. Moreover, we consider certain analogs of I. Hirshman and W. Rudin transforms of Fourier coefficients. Some results are proved to be unimprovable in a certain sense.