Bigravity : A bimetric model of the Universe. Positive and negative   gravitational lensings
  After a short summary of our bimetric model of the Universe, an exact nonlinear solution is built, which demonstrates the existence of solutions for our two coupled field equations system. In addition to the classical positive gravitational lensing, this solution is shown to also lead to negative gravitational lensing, a phenomenon previously described in 1995 (Astrophysics and Space Science). Such negative lensing provides an alternative interpretation for the observed faint magnitudes of high redshift galaxies, so far considered as dwarf galaxies. 
Jean-Pierre Petit, Gilles d'Agostini