  This paper presents the results of collisional evolution calculations for the
Kuiper belt starting from an initial size distribution similar to that produced
by accretion simulations of that region - a steep power-law large object size
distribution that breaks to a shallower slope at r ~1-2 km, with collisional
equilibrium achieved for objects r ~0.5 km. We find that the break from the
steep large object power-law causes a divot, or depletion of objects at r
~10-20 km, which in-turn greatly reduces the disruption rate of objects with r>
25-50 km, preserving the steep power-law behavior for objects at this size. Our
calculations demonstrate that the roll-over observed in the Kuiper belt size
distribution is naturally explained as an edge of a divot in the size
distribution; the radius at which the size distribution transitions away from
the power-law, and the shape of the divot from our simulations are consistent
with the size of the observed roll-over, and size distribution for smaller
bodies. Both the kink radius and the radius of the divot center depend on the
strength scaling law in the gravity regime for Kuiper belt objects. These
simulations suggest that the sky density of r ~1 km objects is ~10^6-10^7
objects per square degree. A detection of the divot in the size distribution
would provide a measure of the strength of large Kuiper belt objects, and
constrain the shape of the size distribution at the end of accretion in the
Kuiper belt.
