Nonstationary three-dimensional contrasting structures

Three-dimensional contrasting structures (CS) occurring in nonlinear diffusion problems with generation are considered assuming that the generation coefficient depends on the concentration. Conditions under which a CS occupying a nonconvex domain in the three-dimensional space disintegrates into several isolated parts in the course of evolution are formulated. This property distinguishes three-dimensional CSs from the two-dimensional ones; the surface of the latter does not change its connectivity until the structure completely disappears.