Fourier–Padé Approximants for Nikishin Systems
نویسندگان
چکیده
منابع مشابه
Sufficient Conditions for the Convergence of Multipoint Hermite-padé Approximants of Nikishin Systems
We consider simultaneous approximation of Nikishin systems of functions by means of rational vector functions which are constructed interpolating along a prescribed table of points. We give sufficient conditions for the uniform convergence of such approximants with a geometric rate.
متن کاملRate of Convergence of Generalized Hermite-padé Approximants of Nikishin Systems
We study the rate of convergence of interpolating simultaneous rational approximations with partially prescribed poles to so called Nikishin systems of functions. To this end, a vector equilibrium problem in the presence of a vector external field is solved which is used to describe the asymptotic behavior of the corresponding second type functions which appear. 1. Generalized Hermite-Padé appr...
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We improve the class of indices for which normality takes place in a Nikishin system and apply this in Hermite-Padé approximation of such systems of functions.
متن کاملMixed Type Multiple Orthogonal Polynomials for Two Nikishin Systems
We study the logarithmic and ratio asymptotic of linear forms constructed from a Nikishin system which satisfy orthogonality conditions with respect to a system of measures generated from another Nikishin system. This construction combines type I and type II multiple orthogonal polynomials. The logarithmic asymptotic of the linear forms is expressed in terms of the extremal solution of an assoc...
متن کاملRelative asymptotic of multiple orthogonal polynomials for Nikishin systems
We prove relative asymptotic for the ratio of two sequences of multiple orthogonal polynomials with respect to Nikishin system of measures. The first Nikishin system N (σ1, . . . , σm) is such that for each k, σk has constant sign on its compact support supp(σk) ⊂ R consisting of an interval e ∆k, on which |σ ′ k| > 0 almost everywhere, and a discrete set without accumulation points in R \ e ∆k...
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ژورنال
عنوان ژورنال: Constructive Approximation
سال: 2008
ISSN: 0176-4276,1432-0940
DOI: 10.1007/s00365-008-9023-1