English

Enveloping superalgebra U(osp(1|2)) and orthogonal polynomials in discrete indeterminate

Representation Theory 2015-06-26 v1

Abstract

Let AA be an associative simple (central) superalgebra over C{\mathbb C} and LL an invariant linear functional on it (trace). Let aata\mapsto a^t be an antiautomorphism of AA such that (at)t=(1)p(a)a(a^t)^ t=(-1)^{p(a)}a, where p(a)p(a) is the parity of aa, and let L(at)=L(a)L(a^t)=L(a). Then AA admits a nondegenerate supersymmetric invariant bilinear form a,b=L(abt)\langle a, b\rangle=L(ab^t). For A=U(sl(2))/mA=U({\mathfrak{sl}}(2))/{\mathfrak{m}}, where m{\mathfrak{m}} is any maximal ideal of U(sl(2))U({\mathfrak{sl}}(2)), Leites and I have constructed orthogonal basis in AA whose elements turned out to be, essentially, Chebyshev (Hahn) polynomials in one discrete variable. Here I take A=U(osp(12))/mA=U({\mathfrak{osp}}(1|2))/{\mathfrak{m}} for any maximal ideal m{\mathfrak{m}} and apply a similar procedure. As a result we obtain either Hahn polynomials over C[τ]{\mathbb C}[\tau], where τ2C\tau^2\in{\mathbb C}, or a particular case of Meixner polynomials, or --- when A=\mboxMat(n+1n)A=\mbox{Mat}(n+1|n) --- dual Hahn polynomials of even degree, or their (hopefully, new) analogs of odd degree. Observe that the nondegenerate bilinear forms we consider for orthogonality are, as a rule, not sign definite.

Keywords

Cite

@article{arxiv.math/0104288,
  title  = {Enveloping superalgebra U(osp(1|2)) and orthogonal polynomials in discrete indeterminate},
  author = {Alexander Sergeev},
  journal= {arXiv preprint arXiv:math/0104288},
  year   = {2015}
}
R2 v1 2026-07-22T16:38:30.917Z