arXiv subjects

A. Bourget

Publications and source records attributed to A. Bourget.

3 recordsLinked to original sources

arXiv2015

A First Szegő's Limit Theorem for a class of non-Toeplitz matrices

We compute the limiting statistical distribution of the eigenvalues of sequences of matrices whose entries satisfy what we call a vanishing mean variation condition and are $μ$-distributed for some probability measure. As an application of our results, we extend the well-known class of Kac-Murdock-Szegő generalized Toeplitz matrices to sequences of matrices whose diagonal entries are modeled by Riemann integrable functions.

math.SP↗

arXiv2009

Interlacing and asymptotic properties of Stieltjes polynomials

Polynomial solutions to the generalized Lamé equation, the \textit{Stieltjes polynomials}, and the associated \textit{Van Vleck polynomials} have been studied since the 1830's, beginning with Lamé in his studies of the Laplace equation on an ellipsoid, and in an ever widening variety of applications since. In this paper we show how the zeros of Stieltjes polynomials are distributed and present two new interlacing theorems. We arrange the Stieltjes polynomials according to their Van Vleck zeros and show, firstly, that the zeros of successive Stieltjes polynomials of the same degree interlace, and secondly, that the zeros of Stieltjes polynomials of successive degrees interlace. We use these results to deduce new asymptotic properties of Stieltjes and Van Vleck polynomials. We also show that no sequence of Stieltjes polynomials is orthogonal.

math.CA↗

arXiv2008

Interlacing and non-orthogonality of spectral polynomials for the Lamé operator

Polynomial solutions to the generalized Lamé equation, the Stieltjes polynomials, and the associated Van Vleck polynomials have been studied since the 1830's in various contexts including the solution of Laplace equations on an ellipsoid. Recently there has been renewed interest in the distribution of the zeros of Van Vleck polynomials as the degree of the corresponding Stieltjes polynomials increases. In this paper we show that the zeros of Van Vleck polynomials corresponding to Stieltjes polynomials of successive degrees interlace. We also show that the spectral polynomials formed from the Van Vleck zeros are not orthogonal with respect to any weight. This furnishes a counterexample, coming from a second order differential equation, to the converse of the well known theorem that the zeros of orthogonal polynomials interlace.

math.CA↗