On the emergence of the Lorentz signature in an expanding universe
  A mechanism producing the transition from an Euclidean to a Loretzian manifold is described. A global Robertson-Walker symmetry is assumed from the large scale data of the visible universe. Allowing for the strain of the manifold as an additional field in the Lagrangian, we interpret the symmetry as a consequence of a global texture defect. The additional term gives rise to a boundary dividing the manifold into an Euclidean plus a Lorentzian region. It is also shown that the presence in the early epoch of homogeneous matter/energy fields preserves the horizon and the signature change across it. The horizon has properties much similar to the ones of the Big Bang of the Standard Model, including the need for a phase transition of the scalar field producing particles and fields as we know them now. 
Angelo Tartaglia
gr-qc astro-ph.CO