Big bounce and inflation from gravitational four-fermion interaction
  The four-fermion gravitational interaction is induced by torsion, and gets dominating on the Planck scale. The regular, axial-axial part of this interaction by itself does not stop the gravitational compression. However, the anomalous, vector-vector interaction results in a natural way both in big bounce and in inflation. 
I.B. Khriplovich
gr-qc astro-ph.CO hep-th