Solution
= Solution
A singular point which is not regular singular is an <irregular singular point>: at least one of $(z-z_0)p(z)$ and $(z-z_0)^2q(z)$ fails to extend holomorphically to $z_0$.
= Solution
A singular point which is not regular singular is an <irregular singular point>: at least one of $(z-z_0)p(z)$ and $(z-z_0)^2q(z)$ fails to extend holomorphically to $z_0$.