Abstract
Padé approximation is the rational generalization of Hermite interpolating polynomial. On its own merits, it has earned a relevant place in the theory of constructive approximation. In this article, we will develop an exhaustive analysis of two-point Padé approximations to Herglotz-Riesz transforms. We study the convergence problem when the poles are partially preassigned. In this analysis, the Stieltjes polynomials on the unit circle naturally arise. Finally, some illustrative numerical examples are discussed.
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Acknowledgements
The authors are indebted to the inspiring work of Claude Brezinski, to whom they want to dedicate this paper on the occasion of his eightieth birthday. They also want to thank the referees for careful reading of an earlier version of the paper which allowed to improve the presentation and which triggered a generalization of several theorems from the 2PTA to the 2PPA case.
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Bultheel, A., Mendoza, C.D. Two-point Padé approximation to Herglotz-Riesz transforms. Numer Algor 92, 269–299 (2023). https://doi.org/10.1007/s11075-022-01467-9
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DOI: https://doi.org/10.1007/s11075-022-01467-9
Keywords
- Padé approximation
- Herglotz-Riesz transform
- Carathéodory function
- Stieltjes polynomial
- Quasi-paraorthogonal
- Unit circle