 Therefore, the metric is
The required solution should satisfy the inequalities

(these conditions specify that one of the functions "a"2, "b"2, "c"2 is small compared to the other two which was also the case with homogeneous models).Inequality means that components γ"a"3 are small in the sense that at any ratio of the shifts "dxa" and "dz", terms with products "dxadz" can be omitted in the square of the spatial length element "dl"2.Therefore, the first approximation to a solution is a metric with γ"a"3 = 0