“…Tridiagonal pairs have been used to investigate the open XXZ spin chain and related models in statistical mechanics (see [16][17][18][19][20][21][22]). The study of tridiagonal pairs has lead to some conceptual advances, such as the bidiagonal pairs/triples (see [43,44]), the billiard arrays (see [148,163]), Hessenberg pairs (see [49][50][51]), and the lowering-raising triples (see [103,104,149]).…”