摘要

Current universe (assumed here to be normal matter on the brave) is pressureless from observations. In this case the energy condition is rho(0) >= 0 and p(0) = 0. By using this condition, brane models can be distinguished. Then, assuming arbitrary component of matter in DGP model, we use four known energy conditions to study the matter oil the brane. If there is nonnormal matter or energy (for example dark energy with w < -1/3) on the brane, the universe is accelerated.