English

Complex exceptional orthogonal polynomials and quasi-invariance

Mathematical Physics 2016-04-20 v1 math.MP Exactly Solvable and Integrable Systems

Abstract

Consider the Wronskians of the classical Hermite polynomials Hλ,l(x):=Wr(Hl(x),Hk1(x),,Hkn(x)),lZ0,H_{\lambda, l}(x):=\mathrm{Wr}(H_l(x),H_{k_1}(x),\ldots, H_{k_n}(x)), \quad l \in \mathbb Z_{\geq 0}, where ki=λi+ni,i=1,,nk_i=\lambda_i+n-i, \,\, i=1,\dots, n and λ=(λ1,,λn)\lambda=(\lambda_1, \dots, \lambda_n) is a partition. G\'omez-Ullate et al showed that for a special class of partitions the corresponding polynomials are orthogonal and dense among all polynomials with certain inner product, but in contrast to the usual case have some degrees missing (so called exceptional orthogonal polynomials). We generalise their results to all partitions by considering complex contours of integration and non-positive Hermitian products. The corresponding polynomials are orthogonal and dense in a finite-codimensional subspace of C[x]\mathbb C[x] satisfying certain quasi-invariance conditions. A Laurent version of exceptional orthogonal polynomials, related to monodromy-free trigonometric Schr\"odinger operators, is also presented.

Keywords

Cite

@article{arxiv.1509.07008,
  title  = {Complex exceptional orthogonal polynomials and quasi-invariance},
  author = {William A. Haese-Hill and Martin A. Hallnäs and Alexander P. Veselov},
  journal= {arXiv preprint arXiv:1509.07008},
  year   = {2016}
}

Comments

18 pages

R2 v1 2026-06-22T11:03:41.907Z