English

Murnaghan-Nakayama rule for the cyclotomic Hecke algebra and applications

Representation Theory 2026-03-12 v2 Combinatorics Quantum Algebra

Abstract

We establish a Murnaghan--Nakayama rule for the irreducible characters of the cyclotomic Hecke algebra Hm,n(q,u)\mathscr H_{m,n}(q,u) on Shoji's standard elements. Combined with Shoji's determinacy result, our formula provides a direct combinatorial route to the full irreducible character table of Hm,n(q,u)\mathscr H_{m,n}(q,u). Our construction is based on our recent multi-parameter Murnaghan--Nakayama rule for Macdonald polynomials and specializes uniformly to several previously known formulas, including those for the complex reflection group of type G(m,1,n)G(m,1,n) and the Iwahori--Hecke algebras of types AA and BB. In a dual framework, using the vertex operator realization of Schur functions, we also derive a complementary iterative formula for irreducible characters on upper multipartitions, which may be viewed as a dual Murnaghan--Nakayama rule. As applications, we obtain a Regev-type formula and a L\"ubeck--Prasad--Adin--Roichman-type formula for cyclotomic Hecke algebras, extending the corresponding formulas for the Iwahori--Hecke algebra of type AA and the complex reflection group, respectively. We further introduce the notion of multiple bitrace for cyclotomic Hecke algebras and give a general combinatorial formula for the multiple bitrace. As a specialization, this yields the second orthogonality relation for irreducible characters of the complex reflection group Wm,nW_{m,n}. For practical computation, we also include in an appendix a SageMath implementation of our Murnaghan--Nakayama rule, which computes individual character values and the full character table.

Keywords

Cite

@article{arxiv.2504.18825,
  title  = {Murnaghan-Nakayama rule for the cyclotomic Hecke algebra and applications},
  author = {Naihuan Jing and Ning Liu},
  journal= {arXiv preprint arXiv:2504.18825},
  year   = {2026}
}

Comments

56 pages. Added SageMath code for the MN rule in Appendix B and made minor improvements to the exposition