Hurwitz numbers for reflection groups II: Parabolic quasi-Coxeter elements

Autor: Douvropoulos, Theo, Lewis, Joel Brewster, Morales, Alejandro H.
Rok vydání: 2022
Předmět:
Zdroj: Journal of Algebra, vol. 641 (2024), pp. 648-715
Druh dokumentu: Working Paper
DOI: 10.1016/j.jalgebra.2023.11.015
Popis: We define parabolic quasi-Coxeter elements in well generated complex reflection groups. We characterize them in multiple natural ways, and we study two combinatorial objects associated with them: the collections $\operatorname{Red}_W(g)$ of reduced reflection factorizations of $g$ and $\operatorname{RGS}(W,g)$ of the relative generating sets of $g$. We compute the cardinalities of these sets for large families of parabolic quasi-Coxeter elements and, in particular, we relate the size $\#\operatorname{Red}_W(g)$ with geometric invariants of Frobenius manifolds. This paper is second in a series of three; we will rely on many of its results in part III to prove uniform formulas that enumerate full reflection factorizations of parabolic quasi-Coxeter elements, generalizing the genus-$0$ Hurwitz numbers.
Comment: v2: 50 pages, minor edits, comments very much welcome!
Databáze: arXiv