English

A formula for the Jack super nabla operator

Combinatorics 2026-04-28 v2

Abstract

We study a Jack analog (p,q)\nabla(\mathbf{p},\mathbf{q}) of the super nabla operator recently introduced by Bergeron, Haglund, Iraci and Romero for Macdonald polynomials. We prove that (p,q)\nabla(\mathbf{p},\mathbf{q}) has a differential expression in the power-sum basis given in terms of Chapuy-Do\l{}e\k{}ga and Nazarov-Sklyanin operators. This result is obtained from a more general formula for the operator G(p,q)G(\mathbf{p},\mathbf{q}) encoding the structure coefficients of Jack characters, from which (p,q)\nabla(\mathbf{p},\mathbf{q}) is obtained by taking the top homogeneous part. A key step of the proof involves establishing that Chapuy-Do\l{}e\k{}ga operators together with a dehomogenized version of Nazarov-Sklyanin operators have a Heisenberg algebra structure. The proof also uses a characterization of the operator G(p,q)G(\mathbf{p},\mathbf{q}) with a family of differential equations, recently established by the author.

Cite

@article{arxiv.2509.18625,
  title  = {A formula for the Jack super nabla operator},
  author = {Houcine Ben Dali},
  journal= {arXiv preprint arXiv:2509.18625},
  year   = {2026}
}

Comments

23 pages; v2 incorporates the referee's suggestions

R2 v1 2026-07-01T05:51:24.446Z