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Bibliographic Details
Main Authors: Lasserre, Jean-Bernard, Xu, Yuan
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2307.10668
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Table of Contents:
  • We extend the polynomial Pell's equation satisfied by univariate Chebyshev polynomials on [--1, 1] from one variable to several variables, using orthogonal polynomials on regular domains that include cubes, balls, and simplexes of arbitrary dimension. Moreover, we show that such an equation is strongly connected (i) to a certificate of positivity (from real algebraic geometry) on the domain, as well as (ii) to the Christoffel functions of the equilibrium measure on the domain. In addition, the solution to Pell's equation reflects an extremal property of orthonormal polynomials associated with an entropy-like criterion.