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arXiv · 0812.0730

Zeros of linear combinations of Laguerre polynomials from different sequences

K Driver·K Jordaan
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Abstract

We study interlacing properties of the zeros of two types of linear combinations of Laguerre polynomials with different parameters, namely $R_n=L_n^{\alpha}+aL_{n}^{\alpha'}$ and $S_n=L_n^{\alpha}+bL_{n-1}^{\alpha'}$. Proofs and numerical counterexamples are given in situations where the zeros of $R_n$, and $S_n$, respectively, interlace (or do not in general) with the zeros of $L_k^{\alpha}$, $L_k^{\alpha'}$, $k=n$ or $n-1$. The results we prove hold for continuous, as well as integral, shifts of the parameter $\alpha$.

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K Driver, K Jordaan. 2008-12-03. Zeros of linear combinations of Laguerre polynomials from different sequences. https://doi.org/10.1016/j.cam.2009.02.091

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