 Some changes occur, however, if the monotonically decreasing function is "b" or "c"; let it be "c".As before, one has equation with the same symbols, and, therefore, the former expressions for the functions "a"(ξ) and "b"(ξ), but equation is replaced by

The major term at large ξ now becomes
so that

The value of "c" as a function of time "t" is again "c" = "c"0"t"/"t"0 but the time dependence of ξ changes.The length of a long era depends on ξ0 according to
On the other hand, the value ξ0 determines the number of oscillations of the functions "a" and "b" during an era (equal to ξ0/2π).