On invariants of Dirac type equation

Three Dirac-like equations, which cannot be reduced one to another by means of nonsingular transformations, are considered. The equations differ in the structural invariants. The previously developed procedure (cyclic structure method) allows one to construct irreducible representations for these equations, to examine the structure of each equation as a whole and each irreducible representation separately. The construction is realized in terms of infinitesimal operators of the Lorentz group and its subgroup, the 3-dimensional rotation group. This allows one to obtain physical interpretation of algebraic constituents for the three types of equations.