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JOURNALS // Chebyshevskii Sbornik // Archive

Chebyshevskii Sb., 2022 Volume 23, Issue 3, Pages 245–248 (Mi cheb1210)

BRIEF MESSAGE

Refinement of the mean angle estimation in the Feyesh Toth problem

D. V. Gorbachev, D. R. Lepetkov

Tula State University (Tula)

Abstract: The Fejes Tóth problem about the maximum $E_{*}$ of the mean value of the sum of angles between lines in $\mathbb{R}^{3}$ with a common center is considered. L. Fejes Tóth suggested that $E_{*}=\frac{\pi}{3}=1.047\ldots$. This conjecture has not yet been proven. D. Bilyk and R.W. Matzke proved that $E_{*}\le 1.110\ldots$. We refine this estimate using an extremal problem of the Delsarte type: $E_{*}\le A_{*}<1.08326$. Using the dual problem $B_{*}$ we show that the solution of the $A_{*}$ problem does not allow us to prove the Fejes Tóth conjecture, since $1.05210<A_{*}$.

Keywords: Fejes Tóth conjecture, unit sphere, Legendre polynomial, linear programming bound, Delsarte problem.

UDC: 517.5

Received: 23.08.2022
Accepted: 14.09.2022

DOI: 10.22405/2226-8383-2022-23-3-245-248



© Steklov Math. Inst. of RAS, 2024