Real-analytic, volume-preserving actions of lattices on 4-manifolds
  We prove that any real-analytic, volume-preserving action of a lattice $\Gamma$ in a simple Lie group with $\Qrank(\Gamma)\geq 7$ on a closed 4-manifold of nonzero Euler characteristic factors through a finite group action. 
Benson Farb and Peter Shalen