Taylor expansions of groups and filtered-formality
Abstract
Let $G$ be a finitely generated group, and let $\Bbbk{G}$ be its group algebra over a field of characteristic $0$. A Taylor expansion is a certain type of map from $G$ to the degree completion of the associated graded algebra of $\Bbbk{G}$ which generalizes the Magnus expansion of a free group. The group $G$ is said to be filtered-formal if its Malcev Lie algebra is isomorphic to the degree completion of its associated graded Lie algebra. We show that $G$ is filtered-formal if and only if it admits a Taylor expansion, and derive some consequences.
- Publication:
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arXiv e-prints
- Pub Date:
- May 2019
- DOI:
- 10.48550/arXiv.1905.10355
- arXiv:
- arXiv:1905.10355
- Bibcode:
- 2019arXiv190510355S
- Keywords:
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- Mathematics - Group Theory;
- Mathematics - Rings and Algebras
- E-Print:
- 19 pages