We prove a Faà di Bruno formula for the Green function in the bialgebra of P-trees, for any polynomial endofunctor P. The formula appears as relative homotopy cardinality of an equivalence of groupoids. © 2013 Elsevier Inc.
- Homotopy cardinality
- Perturbative methods of renormalisation
- Polynomial functors
Gálvez-Carrillo, I., Kock, J., & Tonks, A. (2014). Groupoids and Faà di Bruno formulae for Green functions in bialgebras of trees. Advances in Mathematics, 254, 79-117. https://doi.org/10.1016/j.aim.2013.12.015