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This article is cited in 7 scientific papers (total in 7 papers)
An Extremal Problem for the Derivative of a Rational Function
V. N. Dubininab a Far Eastern Federal University, Vladivostok
b Institute for Applied Mathematics, Far Eastern Branch, Russian Academy of Sciences, Vladivostok
Abstract:
Erdős' well-known problem on the maximum absolute value of the derivative of a polynomial on a connected lemniscate is extended to the case of a rational function. Moreover, under the assumption that certain lemniscates are connected, a sharp upper bound for the absolute value of the derivative of a rational function at any point in the plane different from the poles is found. The role of the extremal function is played by an appropriate Zolotarev fraction.
Keywords:
rational function, Zolotarev fraction, lemniscate, Riemann surface, symmetrization.
Received: 21.04.2016
Citation:
V. N. Dubinin, “An Extremal Problem for the Derivative of a Rational Function”, Mat. Zametki, 100:5 (2016), 732–738; Math. Notes, 100:5 (2016), 714–719
Linking options:
https://www.mathnet.ru/eng/mzm11354https://doi.org/10.4213/mzm11354 https://www.mathnet.ru/eng/mzm/v100/i5/p732
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Abstract page: | 420 | Full-text PDF : | 59 | References: | 66 | First page: | 32 |
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