Leonard pairs having specified end-entries
Abstract
Fix an algebraically closed field and an integer . Let be a vector space over with dimension . A Leonard pair on is an ordered pair of diagonalizable linear transformations and , each acting in an irreducible tridiagonal fashion on an eigenbasis for the other one. Let (resp.\ ) be such an eigenbasis for (resp.\ ). For define a linear transformation such that and if . Define in a similar way. The sequence is called a Leonard system on with diameter . With respect to the basis , let (resp.\ ) be the diagonal entries of the matrix representing (resp.\ ). With respect to the basis , let (resp.\ ) be the diagonal entries of the matrix representing (resp.\ ). It is known that (resp. ) are mutually distinct, and the expressions , are equal and independent of for . Write this common value as . In the present paper we consider the "end-entries" , , , , , , , . We prove that a Leonard system with diameter is determined up to isomorphism by its end-entries and if and only if either (i) and , where , or (ii) and .
Keywords
Cite
@article{arxiv.1409.4333,
title = {Leonard pairs having specified end-entries},
author = {Kazumasa Nomura},
journal= {arXiv preprint arXiv:1409.4333},
year = {2014}
}
Comments
arXiv admin note: substantial text overlap with arXiv:1408.2180