Marco Bruni                                  GGI Florence, October 2006
Perturbations of IS
§For standard linear EoS  P = w r, these variables diverge at the singularity, signaling anisotropy.
§For P= ar + r /rc , after splitting in scalar vector and tensor modes, we find that all the expansion normalised perturbations vanish at the singularity, as we found in the brane case.
§As in the brane case, the r term makes the singularity isotropic, dominating over shear.
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