A THEORY OF PATTERNS

We develop a theory for the analysis of a class of patterns generated on planar isotropic systems. It is developed in the envelope function formalism and applies to patterns that are locally striped. While para meters of the theoretical model depend on the microscopic details of e ach physical system, its general form depends only on the symmetries o f the system. This is suggested to be the reason for the (qualitative) universality of patterns seen in disparate systems.