Integration and geometrization of Rota-Baxter Lie algebras

TL;DR

This paper develops the theory of Rota-Baxter operators on Lie groups and algebroids, establishing their properties, factorizations, and geometric realizations, and introduces new structures like Rota-Baxter Lie groupoids and algebroids.

Contribution

It introduces Rota-Baxter operators on Lie groups and algebroids, proves a factorization theorem, and develops the geometrization of these operators with applications.

Findings

Rota-Baxter operators on Lie groups induce natural factorizations.

The notion of Rota-Baxter Lie algebroids and groupoids is established.

Rota-Baxter Lie algebras and groups can be geometrized via actions on manifolds.

Abstract

This paper first introduces the notion of a Rota-Baxter operator (of weight $1$) on a Lie group so that its differentiation gives a Rota-Baxter operator on the corresponding Lie algebra. Direct products of Lie groups, including the decompositions of Iwasawa and Langlands, carry natural Rota-Baxter operators. Formal inverse of the Rota-Baxter operator on a Lie group is precisely the crossed homomorphism on the Lie group, whose tangent map is the differential operator of weight $1$ on a Lie algebra. A factorization theorem of Rota-Baxter Lie groups is proved, deriving directly on the Lie group level, the well-known global factorization theorems of Semenov-Tian-Shansky in his study of integrable systems. As geometrization, the notions of Rota-Baxter Lie algebroids and Rota-Baxter Lie groupoids are introduced, with the former a differentiation of the latter. Further, a Rota-Baxter Lie algebroid naturally gives rise to a post-Lie algebroid, generalizing the well-known fact for Rota-Baxter Lie algebras and post-Lie algebras. It is shown that the geometrization of a Rota-Baxter Lie algebra or a Rota-Baxter Lie group can be realized by its action on a manifold. Examples and applications are provided for these new notions.