Exotic Stein fillings with arbitrary fundamental group
  For any finitely presentable group $G$, we show the existence of an isolated complex surface singularity link which admits infinitely many exotic Stein fillings such that the fundamental group of each filling is isomorphic to $G$. We also provide an infinite family of closed exotic smooth four-manifolds with the fundamental group $G$ such that each member of the family admits a non-holomorphic Lefschetz fibration over the two-sphere. 
Anar Akhmedov and Burak Ozbagci
math.GT math.AG math.CV math.SG