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This article is cited in 1 scientific paper (total in 1 paper)
On Estimates of Lengths of Lemniscates
O. N. Kosukhin M. V. Lomonosov Moscow State University
Abstract:
For any natural number $n$ and any $C>0$, we obtain an integral formula for calculating the lengths $|L(P_n,C)|$ of the lemniscates
$$
L(P_n,C):=\{z:|P_n(z)|=C\}
$$
of algebraic polynomials $P_n(z):=z^n+c_{n-1}z^{n-1}+\dots+c_0$ in the complex variable $z$ with complex coefficients $c_j$, $j=0, \dots, n-1$, and establish the upper bound for the quantities
$\lambda_n:=\sup\{|L(P_n,1)|: P_n(z)\}$, which is currently best for $3\leq n\leq10^{14}$. We also study the properties of the derivative $S'(C)$ of the area function $S(C)$ of the set $\{z:|P_n(z)|\leq C\}$.
Keywords:
lemniscate of an algebraic polynomial, length of a lemniscate, Lebesgue measure, conformal $n$-sheeted mapping, Jordan domain, Jordan arc.
Received: 19.07.2011 Revised: 29.09.2011
Citation:
O. N. Kosukhin, “On Estimates of Lengths of Lemniscates”, Mat. Zametki, 92:6 (2012), 872–883; Math. Notes, 92:6 (2012), 779–789
Linking options:
https://www.mathnet.ru/eng/mzm9186https://doi.org/10.4213/mzm9186 https://www.mathnet.ru/eng/mzm/v92/i6/p872
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Abstract page: | 598 | Full-text PDF : | 228 | References: | 94 | First page: | 42 |
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