  An understanding of the dynamics of differentially rotating systems is key to
many areas of astrophysics. We investigate the oscillations of a simple system
exhibiting differential rotation, and discuss issues concerning the role of
corotation points and the emergence of dynamical instabilities. This problem is
of particular relevance to the emission of gravitational waves from oscillating
neutron stars, which are expected to possess significant differential rotation
immediately after birth or binary merger.
