Skip to content

Perfectness of partial Christoffel transforms of Nikishin systems

Rostyslav Kozhan

math.CAarXiv:2611.01395

Abstract

We study multiple orthogonal polynomial systems obtained from a Nikishin system of two measures by applying a Christoffel transform to one of the measures at a point x=x0. We show that if x0 separates the supports of the generating measures, then the modified systems remain perfect. As an application, we prove that the type I multiple orthogonal polynomials of a Nikishin system have no zeros in the gap between the supports of its generating measures.

Create a lesson