English

Leonard pairs having zero-diagonal TD-TD form

Rings and Algebras 2015-03-19 v1

Abstract

Fix an algebraically closed field F\mathbb{F} and an integer n1n \geq 1. Let Matn(F)\text{Mat}_n(\mathbb{F}) denote the F\mathbb{F}-algebra consisting of the n×nn \times n matrices that have all entries in F\mathbb{F}. We consider a pair of diagonalizable matrices in Matn(F)\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 Matn(F)\text{Mat}_{n}(\mathbb{F}). In the present paper, we find all Leonard pairs A,AA,A^* in Matn(F)\text{Mat}_{n}(\mathbb{F}) such that each of AA and AA^* is irreducible tridiagonal with all diagonal entries 00. This solves a problem given by Paul Terwilliger.

Keywords

Cite

@article{arxiv.1503.05262,
  title  = {Leonard pairs having zero-diagonal TD-TD form},
  author = {Kazumasa Nomura},
  journal= {arXiv preprint arXiv:1503.05262},
  year   = {2015}
}
R2 v1 2026-06-22T08:55:47.169Z