A partial dictionary between universal central extensions and orthogonal polynomials in the superelliptic Krichever--Novikov setting
Abstract
Let , let have simple roots, and let be the coordinate ring of the associated superelliptic curve. The derivation algebra and the current algebra (for a simple Lie algebra) each admit a universal central extension whose center is multi-dimensional and carries linear algebraic relations among its basis elements. We establish a systematic dictionary between these relations and families of orthogonal polynomials in the parameter encoding the branch locus of . The dictionary has three canonical entries: (1)~the basis reduction relations in the center of are exactly the three-term recurrence of an orthogonal polynomial family; (2)~the generating function of the center satisfies the Sturm--Liouville ODE of that family; (3)~the mixed-sector -cocycle equals the Legendre antiderivative in the quadratic case. We prove the dictionary completely for (Legendre polynomials) and for the quartic palindromic case . In the quadratic case, palindromic symmetry forces the recurrence to be the Legendre three-term recurrence; in the quartic case, the odd sector is Legendre and the even sector satisfies a two-component recurrence with palindromic coefficients. We conjecture this pattern -- palindromic forcing symmetric recurrence coefficients -- holds in all even degrees. The same dictionary governs the K\"{a}hler side : all sectors reduce to the sector- family at a rescaled parameter, and the recurrence and ODE entries are canonical while the mixed-cocycle entry is partially choice-dependent.
Keywords
Cite
@article{arxiv.2605.02530,
title = {A partial dictionary between universal central extensions and orthogonal polynomials in the superelliptic Krichever--Novikov setting},
author = {Felipe Albino dos Santos},
journal= {arXiv preprint arXiv:2605.02530},
year = {2026}
}