(* invariant sur union_mpl_0, sens direct, 0 *)

Lemma union_s0d_2_1 :
forall (d : preDTA) (pl : prec_list) (s0 s1 : state) (tl : term_list),
mpl_compat (M1 prec_list (Npos 1) pl) (M2 prec_list s0 s1) ->
state_reconnait d (M1 prec_list (Npos 1) pl) (app (Npos 1) tl) ->
state_reconnait d (union_mpl_0 (Npos 1) pl (M2 prec_list s0 s1))
(app (Npos 1) tl).