Topological contributions to fermionic correlators and nonperturbative   aspects of QCD in two dimensions
  We analyze the formation of fermionic condensates in two dimensional quantum chromodynamics for matter in the fundamental representation of the gauge group. We show that a topological regular instanton background is crucial in order to obtain nontrivial correlators. We discuss both massless and massive cases. 
Hugo Christiansen (CBPF - Rio de Janeiro)