The cyclotomic Grothendieck-Teichm\"{u}ller group and the motivic Galois group

Abstract

We show that the level 2 case of the cyclotomic Grothendieck-Teichm\"{u}ller groups introduced by Enriquez coincides with the motivic Galois group of mixed Tate motives over $\mathbb{Z}[1/2]$.