Post-Lie algebras of derivations and regularity structures

Abstract: Given a commutative algebra $A$, we exhibit a canonical structure of post-Lie algebra on the space $A\otimes Der(A)$ where $Der(A)$ is the space of derivations on $A$, in order to use the machinery given in [Guin & Oudom 2008] and [Ebrahimi-Fard & Lundervold & Munthe-Kaas 2015] and to define a Hopf algebra structure on the associated enveloping algebra with a natural action on $A$. We apply these results to the setting of [Linares & Otto & Tempelmayr 2023], giving a simpler and more efficient construction of their action and extending the recent work [Bruned & Katsetsiadis]. This approach gives an optimal setting to perform explicit computations in the associated structure group.