English

Mapping class group actions from Hopf monoids and ribbon graphs

Quantum Algebra 2023-06-13 v2

Abstract

We show that any pivotal Hopf monoid HH in a symmetric monoidal category C\mathcal{C} gives rise to actions of mapping class groups of oriented surfaces of genus g1g \geq 1 with n1n \geq 1 boundary components. These mapping class group actions are given by group homomorphisms into the group of automorphisms of certain Yetter-Drinfeld modules over HH. They are associated with edge slides in embedded ribbon graphs that generalise chord slides in chord diagrams. We give a concrete description of these mapping class group actions in terms of generating Dehn twists and defining relations. For the case where C\mathcal{C} is finitely complete and cocomplete, we also obtain actions of mapping class groups of closed surfaces by imposing invariance and coinvariance under the Yetter-Drinfeld module structure.

Keywords

Cite

@article{arxiv.2002.04089,
  title  = {Mapping class group actions from Hopf monoids and ribbon graphs},
  author = {Catherine Meusburger and Thomas Voß},
  journal= {arXiv preprint arXiv:2002.04089},
  year   = {2023}
}

Comments

60 pages, 21 figures

R2 v1 2026-06-23T13:37:32.989Z