satisfies the
differential equation
where again
. This equation is of order
. In consequence of (16.19.1) we may assume, without
loss of generality, that
. With the classification of
§16.8(i), when
the only singularities of
(16.21.1) are a regular singularity at
and an irregular
singularity at
. When
the only singularities of
(16.21.1) are regular singularities at
,
,
and
.