intros goal l b0 b1 gamma work context j j1 less1 spec0.
apply rule_vimp_a_gamma with j1; try assumption.
apply rule_vimp_conj_gamma; assumption.
Qed.
(****************************************************)
(* rules for   ...(cons (vimp l (OrF a b)) gamma)... *)

Lemma rule_vimp_falsum_or_a_gamma :
forall (goal : form) (l : list Int) (a : form) (gamma : flist)
(work : nf_list) (context : flist) (j : Int),
search_spec goal (vimp l a :: gamma) work context j ->
search_spec goal (vimp l (OrF Falsum a) :: gamma) work context j.