Vol. 4 No. 2 (2012)

Published: 2013-01-24

Articles

  • Articles

    On some optimizations of trigonometric interpolation using Fourier discrete coefficients

    Arnak Poghosyan
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    Abstract

    We investigate convergence of the rational-trigonometric-polynomial interpolations which perform convergence acceleration of the classical trigonometric interpolation by sequential application of polynomial and rational corrections. Rational corrections contain unknown parameters which determination outlines the behavior of the interpolations in different frameworks. We consider approach for determination of the unknown parameters by minimization of the constants of the asymptotic errors. We perform theoretical and numerical analysis of such optimal interpolations.

    References
  • Articles

    On a convergence of the Fourier-Pade approximation

    Arnak Poghosyan
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    Abstract

    We consider convergence acceleration of the truncated Fourier series by sequential application of polynomial and rational corrections. Polynomial corrections are performed along the ideas of the Krylov-Lanczos approximation. Rational corrections contain unknown parameters which determination is a crucial problem for realization of the rational approximations. We consider approach connected with the Fourier-Pade approximations. This rational-trigonometric-polynomial approximation we continue calling the Fourier-Pade approximation. We investigate its convergence for smooth functions in different frameworks and derive the exact constants of asymptotic errors. Detailed analysis and comparisons of different rational-trigonometric-polynomial approximations are performed and the convergence properties of the Fourier-Pade approximation are outlined. In particular, fast convergence of the Fourier-Pade approximation is observed in the regions away from the endpoints.

    References
  • Articles

    Coefficient inequality for certain subclass of analytic functions

    D. Vamshee Krishna, T. Ramreddy
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    Abstract

    The objective of this paper is to an obtain an upper bound to the second Hankel determinant $|a_{2}a_{4}-a_{3}^{2}|$ for the function $f$, belonging to a certain subclass of analytic functions, using Toeplitz determinants.

    References