Given an initial distribution of sand in an Abelian sandpile, what final state does it relax to after all possible avalanches have taken place? In d = 3*, we show that this problem is P-complete, so that explicit simulation of the system is almost certainly necessary. We also show that the...

Evolution is applied to the development of parallel digital computer programs. The environment is a shared memory virtual computer containing a population of parallel computer programs. Although the digital computer is a very different environment than the ecology of the Earth, evolution is...