Projective properties of Lorentzian surfaces
  We investigate projective properties of Lorentzian surfaces. In particular, we prove that if T is a non flat torus, then the index of its isometry group in its projective group is at most two. We also prove that any topologically finite noncompact surface can be endowed with a metric having a non isometric projective transformation of infinite order. 
Pierre Mounoud (IMB)
math.DG