A description of Fredholm functionals extremal distribution, bifurcating from minima points with two-dimensional degeneration and features of the sixth order is given. The main illustrating exampleistheproblemofheterogeneouscrystalferroelectricphases branching (based on helical model). We use modified Lyapunov – Schmidt method ( reduction to key function on Rn), equipped with the elements of singularities theory of smooth functions. Emphasis is put on key function with square symmetry.
