English

Leonard pairs from 24 points of view

Rings and Algebras 2007-05-23 v1 Mathematical Physics math.MP

Abstract

Let KK denote a field and let VV denote a vector space over KK with finite positive dimension. We consider a pair of linear transformations A:VVA:V\to V and A:VVA^*:V\to V that satisfy both conditions below: (i) There exists a basis for VV with respect to which the matrix representing AA is diagonal and the matrix representing AA^* is irreducible tridiagonal. (ii) There exists a basis for VV with respect to which the matrix representing AA^* is diagonal and the matrix representing AA is irreducible tridiagonal. We call such a pair a {\it Leonard pair} on VV. Referring to the above Leonard pair, we investigate 24 bases for VV on which the action of AA and AA^* takes an attractive form. With respect to each of these bases, the matrices representing AA and AA^* are either diagonal, lower bidiagonal, upper bidiagonal, or tridiagonal.

Keywords

Cite

@article{arxiv.math/0406577,
  title  = {Leonard pairs from 24 points of view},
  author = {Paul Terwilliger},
  journal= {arXiv preprint arXiv:math/0406577},
  year   = {2007}
}

Comments

50 pages, 1 figure

R2 v1 2026-07-22T17:07:16.948Z