intros a gamma work context minimal0.
unfold minimal in |- *.
intros b k k_is_mon k_forces_gamma in_b.
apply minimal0; try assumption.
apply forces_gamma_shift_gamma_work; assumption.
Qed.
(*************************************************************************)

Lemma minimal_cons_gamma_cons_context :
forall (gamma : flist) (work : nf_list) (context : flist) (a : form),
minimal gamma work context -> minimal (a :: gamma) work (a :: context).