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We study the anisotropic Big Bang cosmology for a general non-linear equation of state (EoS) in standard general relativity cosmology in early times. According to brane world cosmology and loop quantum gravity which introduce a quadratic term in the energy density, we study a non-linear EoS with a general nonlinear term in the energy density. We show that this general non-linear term isotropize the universe at early times. And also, we find out this model has a phantom like behavior for special case., Comment: 10 pages, no figures

Using non-linear equation of state for pressure and density energy, we show that the universe is began with a smooth and isotropic bounce. We use a non-linear equation of state which is a binary mixture of perfect fluid and dark energy. We show that in order to preserve a smooth and isotropic bounce, the source for contraction before the bounce, must have an equation of state with $\omega>1$ (Ekpyrotic matter) and a dark energy with positive pressure., Comment: 11 pages, no figures