The asymptotic accuracy of rational best approximations to ez on a disk |
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Authors: | Lloyd N Trefethen |
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Institution: | Courant Institute of Mathematical Sciences, New York University, New York, New York 10012 U.S.A. |
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Abstract: | The method described by D. Braess (J. Approx. Theory40 (1984), 375–379) is applied to study approximation of ez on a disk rather than an interval. Let Emn be the distance in the supremum norm on ¦z¦ ? ? from ez to the set of rational functions of type (m, n). The analog of Braess' result turns out to be as m + n → ∞ This formula was obtained originally for a special case by E. Saff (J. Approx. Theory9 (1973), 97–101). |
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Keywords: | 30E10 41A20 41A21 41A50 |
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