  We have established that the most general form of Hamiltonian that preserves
fermionic coherent states stable in time, is that of the nonstationary free
fermionic oscillator. This is to be compared with the earlier result of boson
coherence Hamiltonian, which is of the more general form of the nonstationary
forced bosonic oscillator. If however one admits Grassmann variables as
Hamiltonian parameters then the coherence Hamiltonian takes again the form of
(Grassmannian fermionic) forced oscillator.
