Solution
= Solution
For $w''+P(z)w'+Q(z)w=0$, a finite point $z_0$ is regular singular when
$$
(z-z_0)P(z),
\qquad (z-z_0)^2Q(z)
$$
extend analytically to $z_0$. Inspection shows that $a,b,c$ satisfy these conditions. There are no other finite singularities; with the Fuchs relation on the six exponents, the point at infinity is ordinary in the corresponding sphere description.