 Consider a long era, during which 2 out of the 3 functions "a", "b", "c" (let them be "a" and "b") undergo small oscillations while the third function ("c") decreases monotonously.The latter function quickly becomes small; consider the solution just in the region where one can ignore "c" in comparison to "a" and "b".The calculations are first done for the Type IX space model by substituting accordingly λ = μ = ν = 1.