“…The nontrivial groups (strata) , their restriction d to the diagonal, o as the restriction to off-diagonal elements, the orbit length o of the entire group , the number of pre-images of the primary invariants p (= the orbit length of , acting on the cross product of the space of diagonals and the space of off-diagonal), and the maximal number of leaves of this stratum, l. symmetry group. In the theory of Higgs potentials, the connection between symmetry breaking, energy functions and the orbit space has been known for some time (see the work by Abud & Sartori [1,2]). For phase transitions in crystals, however, the situation is usually more complicated, since the orbit space is high-dimensional.…”