Two-mode branching of ferroelectric phase heterogeneous crystals of singular phase of the sixth order

A description of the distribution of extremals of Fredholm functionals bifurcation points of the minima of 2-dimensional features of degeneration and the sixth order. The main illustrating example is the task of branching ferroelectric phase heterogeneous crystals. We use a modified the Lyapunov—Schmidt method, equipped with the elements of the theory of singularities of smooth functions.