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arXiv · 1503.05262

Leonard pairs having zero-diagonal TD-TD form

Kazumasa Nomura
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Abstract

Fix an algebraically closed field $\mathbb{F}$ and an integer $n \geq 1$. Let $\text{Mat}_n(\mathbb{F})$ denote the $\mathbb{F}$-algebra consisting of the $n \times n$ matrices that have all entries in $\mathbb{F}$. We consider a pair of diagonalizable matrices in $\text{Mat}_{n}(\mathbb{F})$, each acting in an irreducible tridiagonal fashion on an eigenbasis for the other one. Such a pair is called a Leonard pair in $\text{Mat}_{n}(\mathbb{F})$. In the present paper, we find all Leonard pairs $A,A^*$ in $\text{Mat}_{n}(\mathbb{F})$ such that each of $A$ and $A^*$ is irreducible tridiagonal with all diagonal entries $0$. This solves a problem given by Paul Terwilliger.

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Kazumasa Nomura. 2015-03-18. Leonard pairs having zero-diagonal TD-TD form. https://arxiv.org/abs/1503.05262

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