English

The polytope algebra of generalized permutahedra

Combinatorics 2025-02-14 v3

Abstract

The polytope subalgebra of deformations of a zonotope can be endowed with the structure of a module over the Tits algebra of the corresponding hyperplane arrangement. We explore this construction and find relations between statistics on (signed) permutations and the module structure in the case of (type B) generalized permutahedra. In type B, the module structure surprisingly reveals that any family of generators (via signed Minkowski sums) for generalized permutahedra of type B will contain at least 2d12^{d-1} full-dimensional polytopes. We find a generating family of simplices attaining this minimum. Finally, we prove that the relations defining the polytope algebra are compatible with the Hopf monoid structure of generalized permutahedra.

Keywords

Cite

@article{arxiv.2009.05876,
  title  = {The polytope algebra of generalized permutahedra},
  author = {Jose Bastidas},
  journal= {arXiv preprint arXiv:2009.05876},
  year   = {2025}
}

Comments

Comments welcome. V2 Added references, the results for generalized permutahedra of type A and B are now in separate sections. V3 Final version in _Algebraic Combinatorics_