The tensor momentum equation and the conservation of mass equation, i.e., a 1 a 2 a 3 = a 1 ( 0 ) a 2 ( 0 ) a 3 ( 0 ) provides us with ten equations for the ten unknowns, a 1 , a 2 , a 3 , p c , Λ Λ , Ω Ω .