Activators and Inhibitors in Pattern Formation

A wide class of diffusion reaction equations with activator-inhibitor reaction dynamics are studied analytically. It is shown that when the inhibitor diffuses much faster than the activator, patterns with large amplitude nonuniformities may exist. It is further shown that with a slightly nonuniform source of activator, the patterns which emerge from the time dependent process have a directional preference. The results given coincide with the numerical results of Gierer and Meinhardt [6].