  The O(3) Skyrme system in two space dimensions admits topological soliton
solutions. This paper studies the transition between the high-density
crystalline phase of such solitons and the low-density phase where there are
multi-Skyrmions localized in space. The details depend crucially on the choice
of the potential function. Two such choices are investigated: in the first
system, multi-Skyrmions at low density form a ring; while in the second, there
is an explicit crystal solution, and the preferred low-density configurations
are chunks of this crystal. The second system is a particularly good analogue
of three-dimensional Skyrmions.
