Displaying similar documents to “An analogue of Montel’s theorem for some classes of rational functions”

Rational interpolants with preassigned poles, theoretical aspects

Amiran Ambroladze, Hans Wallin (1999)

Studia Mathematica

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Let ⨍ be an analytic function on a compact subset K of the complex plane ℂ, and let r n ( z ) denote the rational function of degree n with poles at the points b n i i = 1 n and interpolating ⨍ at the points a n i i = 0 n . We investigate how these points should be chosen to guarantee the convergence of r n to ⨍ as n → ∞ for all functions ⨍ analytic on K. When K has no “holes” (see [8] and [3]), it is possible to choose the poles b n i i , n without limit points on K. In this paper we study the case of general compact sets K, when...

Asymptotic distribution of poles and zeros of best rational approximants to x α on [0,1]

E. Saff, H. Stahl (1995)

Banach Center Publications

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Let r n * n n be the best rational approximant to f ( x ) = x α , 1 > α > 0, on [0,1] in the uniform norm. It is well known that all poles and zeros of r n * lie on the negative axis < 0 . In the present paper we investigate the asymptotic distribution of these poles and zeros as n → ∞. In addition we determine the asymptotic distribution of the extreme points of the error function e n = f - r n * on [0,1], and survey related convergence results.