On the Drinfeld generators of grt_1(k) and Gamma-functions for associators
arXiv:math/0502084
Abstract
We prove that the Drinfeld generators of grt_1(k) span the image of this Lie algebra in the abelianization of the commutator of the free Lie algebra with two generators. We show that this result implies Gamma-function formulas for arbitrary associators.