Rigidity of an Isometric $SL(3,\mathbb{R})$-Action
  We characterize the universal covering of connected analytic pseudo-Riemannian manifolds which admit a non-trivial and isometric action of the simple Lie group $SL(3,\mathbb{R})$ with a dense orbit preserving a finite volume. If such manifold is also weakly irreducible we prove that $M$ is isometric to, or a quotient space of, a simple Lie group containing $SL(3,\mathbb{R})$. 
Raul Quiroga-Barranco, Eli Roblero-M\'endez
math.DG