Topological relaxation of entangled flux lattices: Single vs collective   line dynamics
  A symbolic language allowing to solve statistical problems for the systems with nonabelian braid-like topology in 2+1 dimensions is developed. The approach is based on the similarity between growing braid and "heap of colored pieces". As an application, the problem of a vortex glass transition in high-T_c superconductors is re-examined on microscopic level 
R.Bikbov, S.Nechaev