The zeros of linear combinations of orthogonal polynomials

  • Authors:
  • A. F. Beardon;K. A. Driver

  • Affiliations:
  • Centre for Mathematical Studies, University of Cambridge, Cambridge, UK;The John Knopfmacher Centre for Applicable Analysis and Number Theory, School of Mathematics, University of the Witwatersrand, Johannnesburg, South Africa

  • Venue:
  • Journal of Approximation Theory
  • Year:
  • 2005

Quantified Score

Hi-index 0.00

Visualization

Abstract

Let {pn} be a sequence of monic polynomials with pn of degree n, that are orthogonal with respect to a suitable Borel measure on the real line. Stieltjes showed that if m n and x1,.....,xn are the zeros of pn with x1 xn then there are m distinct intervals f the form (xj, xj+1) each containing one zero of Pm. Our main theorem proves a similar result with Pm replaced by some linear combinations of p1,....,pm. The interlacing of the zeros of linear combinations of two and three adjacent orthogonal polynomials is also discussed.