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Cohomologies of difference Lie groups and van Est theorem

Jun Jiang, Yunnan Li, Yunhe Sheng

Abstract

A difference Lie group is a Lie group equipped with a difference operator, equivalently a crossed homomorphism with respect to the adjoint action. In this paper, first we introduce the notion of a representation of a difference Lie group, and establish the relation between representations of difference Lie groups and representations of difference Lie algebras via differentiation and integration. Then we introduce a cohomology theory for difference Lie groups and justify it via the van Est theorem. Finally, we classify abelian extensions of difference Lie groups using the second cohomology group as applications.

Cohomologies of difference Lie groups and van Est theorem

Abstract

A difference Lie group is a Lie group equipped with a difference operator, equivalently a crossed homomorphism with respect to the adjoint action. In this paper, first we introduce the notion of a representation of a difference Lie group, and establish the relation between representations of difference Lie groups and representations of difference Lie algebras via differentiation and integration. Then we introduce a cohomology theory for difference Lie groups and justify it via the van Est theorem. Finally, we classify abelian extensions of difference Lie groups using the second cohomology group as applications.
Paper Structure (11 sections, 17 theorems, 88 equations)

This paper contains 11 sections, 17 theorems, 88 equations.

Key Result

Lemma 2.7

Let $(G, \mathcal{D})$ be a difference Lie group. Then $\mathcal{D}(e_G)=e_G$, where $e_G$ is the unit of $G$, and

Theorems & Definitions (51)

  • Definition 2.1
  • Example 2.2
  • Example 2.3
  • Example 2.4
  • Example 2.5
  • Example 2.6
  • Lemma 2.7
  • proof
  • Lemma 2.8
  • proof
  • ...and 41 more