Associahedra, cyclohedra and inversion of power series
Combinatorics
2020-10-28 v1
Abstract
We introduce the Hopf monoid of sets of cycles and paths, which contains the Fa\`a di Bruno Hopf monoid as a submonoid. We give cancellation-free and grouping-free formulas for its antipode, one in terms of tubings and one in terms of \emph{pointed} noncrossing partitions. We provide an explicit description of the group of characters of this Hopf monoid in terms of pairs of power series. Using graph associahedra, we relate paths and cycles to associahedra and cyclohedra, respectively. We give formulas for inversion in the group of characters in terms of the faces of these polytopes.
Cite
@article{arxiv.2010.14283,
title = {Associahedra, cyclohedra and inversion of power series},
author = {Marcelo Aguiar and Jose Bastidas},
journal= {arXiv preprint arXiv:2010.14283},
year = {2020}
}
Comments
18 pages, 5 figures, comments welcome