  In paper within the model with a maximal mass M and with use of anti de
Sitter space is considered the Dirac equation properties for a fermion of mass
m on the mass surface. The paper shows that free Hamiltonian and Hamiltonian
with interaction are pseudo-Hermitian. If we accept the appropriate rules of
use of pseudo-Hermitian Hamiltonians, we can construct the consistent quantum
theory with final results obtained using the ordinary Dirac equation.
