Actions of automorphism groups of free groups on spaces of Jacobi diagrams. I

We consider an action of the automorphism group Aut(F n ) free F rank on filtered vector space A d (n) Jacobi diagrams degree oriented arcs. This induces associated graded (n), which is identified with B open diagrams, general linear GL(n,?) and Lie algebra IA-automorphism its lower central series. use these actions to study )-module structure (n). In particular, we case where d=2 in detail give indecomposable decomposition 2 also construct a polynomial functor 2d from opposite category finitely generated groups spaces, includes for all n?0.