Abstract:
For each p>1p>1, we obtain a lower bound for the distances to the real axis from the poles of simplest fractions (i.e., logarithmic derivatives of polynomials) bounded by 1 in the norm of LpLp on this axis; this estimate improves the first estimate of such kind derived by Danchenko in 1994. For p=2p=2, the estimate turns out to be sharp. Similar estimates are obtained for the distances from the poles of simplest fractions to the vertices of angles and rays.
Citation:
P. A. Borodin, “Estimates of the Distances to Direct Lines and Rays from the Poles of Simplest Fractions Bounded in the Norm of LpLp on These Sets”, Mat. Zametki, 82:6 (2007), 803–810; Math. Notes, 82:6 (2007), 725–732
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\by P.~A.~Borodin
\paper Estimates of the Distances to Direct Lines and Rays from the Poles of Simplest Fractions Bounded in the Norm of~$L_p$ on These Sets
\jour Mat. Zametki
\yr 2007
\vol 82
\issue 6
\pages 803--810
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\transl
\jour Math. Notes
\yr 2007
\vol 82
\issue 6
\pages 725--732
\crossref{https://doi.org/10.1134/S0001434607110168}
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Linking options:
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https://doi.org/10.4213/mzm4180
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This publication is cited in the following 10 articles:
P. A. Borodin, K. S. Shklyaev, “Density of quantized approximations”, Russian Math. Surveys, 78:5 (2023), 797–851
M. A. Komarov, “Approximation by linear fractional transformations of simple partial fractions and their differences”, Russian Math. (Iz. VUZ), 62:3 (2018), 23–33
Chunaev P., Danchenko V., “Quadrature Formulas With Variable Nodes and Jackson-Nikolskii Inequalities For Rational Functions”, J. Approx. Theory, 228 (2018), 1–20
V. I. Danchenko, M. A. Komarov, P. V. Chunaev, “Extremal and approximative properties of simple partial fractions”, Russian Math. (Iz. VUZ), 62:12 (2018), 6–41
P. A. Borodin, “Density of a semigroup in a Banach space”, Izv. Math., 78:6 (2014), 1079–1104
V. I. Danchenko, “Convergence of simple partial fractions in Lp(R)”, Sb. Math., 201:7 (2010), 985–997
V. I. Danchenko, E. N. Kondakova, “Chebyshev's alternance in the approximation of constants by simple partial fractions”, Proc. Steklov Inst. Math., 270 (2010), 80–90
V. Yu. Protasov, “Approximation by simple partial fractions and the Hilbert transform”, Izv. Math., 73:2 (2009), 333–349
P. A. Borodin, “Approximation by simple partial fractions on the semi-axis”, Sb. Math., 200:8 (2009), 1127–1148
E. N. Kondakova, “Interpolyatsiya naiprosteishimi drobyami”, Izv. Sarat. un-ta. Nov. ser. Ser.: Matematika. Mekhanika. Informatika, 9:2 (2009), 30–37