Lines crossing a tetrahedron and the Bloch group
  We consider a simple modification of the Chow group CH^2(Spec(k),3) using only linear subvarieties in affine spaces and show that it maps surjectively to the Bloch group B(k) for any infinite field k. We also describe the kernel of this map. 
Kevin Hutchinson and Masha Vlasenko
math.NT math.KT