Matrix-space dynamics with allowance for third-order terms in the Lagrangian

The general principles of the matrix-space dynamics formulated in earlier investigations (Teor. Mat. Fiz., 1, 222 (1969); 3, 183 (1970)) are used to construct a Lagrangian in which not only the second-order but also the third-order terms in powers of the small deviation from the vacuum state are taken into account. It is shown that a suitable transformation can eliminate all the cubic terms in the expressions for the physical quantities. This corresponds to the absence of terms proportional to $\psi^3$ in the analogous expressions of a spinor theory.