  We investigate the stability of the relativistic three-fermion system with a
zero-range force in the light front form. In particular, introducing an
invariant cut-off, we study the dependence of the bound state on the coupling
strength also for cases where the two-fermion system is unbound. The
relativistic Thomas collapse is discussed by solving the fully coupled integral
equation system. Furthermore, we explicitly investigate the ground state mass
of the three-fermion system and compare to previous simplified calculations.
