Observe that in the case ˜c ≡ 0 Theorem 5 reduces to Theorem 1 (i). Indeed, if ∞
r1−q = ∞ then h ≡ 1 is the principal solution of the one term equation (8) and
(20) is the same as (10). Note also that Theorems 2–4 can be extended along the
line treated in this subsection as well, we refer to [12], [17] for more details.