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arXiv · 2611.01395

Perfectness of partial Christoffel transforms of Nikishin systems

Rostyslav Kozhan
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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 $x=x_0$. We show that if $x_0$ 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.

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BibTeXRIS

Rostyslav Kozhan. 2026-11-01. Perfectness of partial Christoffel transforms of Nikishin systems. https://arxiv.org/abs/2611.01395

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