  This paper considers the quantum collapse of infinitesimally thin dust shells
in 2+1 gravity. In 2+1 gravity a shell is no longer a sphere but a ring of
matter. The classical equation of motion has been considered by Peleg and Steif
and Cristosomo and Olea. The minisuperspace quantum problem can be reduced to
that of a harmonic oscillator in terms of the curvature radius of the shell,
allowing the use of well-known methods to find the motion of coherent wave
packets that give the quantum collapse of the shell. Classically, as the radius
of the shell falls below a certain point, a horizon forms. In the quantum
problem one can define various quantities that give "indications" of horizon
formation. Without proper definitions of a "horizon" in quantum gravity, these
can be nothing but indications.
