Exponential formulas for models of complex reflection groups
Abstract
In this paper we find some exponential formulas for the Betti numbers of the De Concini-Procesi minimal wonderful models Y_{G(r,p,n)} associated to the complex reflection groups G(r,p,n). Our formulas are different from the ones already known in the literature: they are obtained by a new combinatorial encoding of the elements of a basis of the cohomology by means of set partitions with weights and exponents. We also point out that a similar combinatorial encoding can be used to describe the faces of the real spherical wonderful models of type A_{n-1}=G(1,1,n), B_n=G(2,1,n) and D_n=G(2,2,n). This provides exponential formulas for the f-vectors of the associated nestohedra: the Stasheff's associahedra (in this case closed formulas are well known) and the graph associahedra of type D_n.
Keywords
Cite
@article{arxiv.1507.02090,
title = {Exponential formulas for models of complex reflection groups},
author = {Giovanni Gaiffi},
journal= {arXiv preprint arXiv:1507.02090},
year = {2015}
}
Comments
with respect to v.1: misprint corrected in Example 3.1