Free post-groups, post-groups from group actions, and post-Lie algebras

Abstract

After providing a short review on the recently introduced notion of post-group by Bai, Guo, Sheng and Tang, we exhibit post-group counterparts of important post-Lie algebras in the literature, including the infinite-dimensional post-Lie algebra of Lie group integrators. The notion of free post-group is examined, and a group isomorphism between the two group structures associated to a free post-group is explicitly constructed.

Inaccurracy corrected by considering weak post-groups (recently introduced by S. Wang, arXiv:2307.10535)