ABSTRACT
Theorem 4.l(ii) then shows that in the resulting asymptotic series the variations of the coefficients converge at the singularity z = 0. Unfortunately, as suggested by Exercise 4.1 and verifiable by means of (2.09) and (2.10), these variations diverge at the other singularity z = co. To overcome this obstacle we replace z by vz; thus
With
Theorem 4.l(ii) and Exercise 4.1 show that the variations of the new coefficients converge at both z = 0 and z = co.
