  Gregory and Laflamme (hep-th/9301052) have argued that an instability causes
the Schwarzschild black string to break up into disjoint black holes. On the
other hand, Horowitz and Maeda (arXiv:hep-th/0105111) derived bounds on the
rate at which the smallest sphere can pinch off, showing that, if it happens at
all, such a pinch-off can occur only at infinite affine parameter along the
horizon. An interesting point is that, if a singularity forms, such an infinite
affine parameter may correspond to a finite advanced time -- which is in fact a
more appropriate notion of time at infinity. We argue below that pinch-off at a
finite advanced time is in fact a natural expectation under the bounds derived
by Horowitz and Maeda.
