"Double swallow-tail" singularity and glass-glass transition in a quasibinary system

The system with the square shoulder (SS) potential is considered in the frame of Mode Coupling Theory (MCT) approach. An approximation for the structure factor is used that emphasizes the quasibinary character of the system. The qualitative phase diagram is constructed that includes continuous and discontinuous glass-glass transitions. The phase diagram is governed by two swallow tails connected with two $A_4$ singularities.