(*SUBJECT, Property and TransFunc*)
Ltac OpDontChangeStPSS :=
intros s t Sub SS TF; inversion TF;
match goal with
| id:(s = t) |- _ => rewrite <- id; auto
end.
Ltac OpDontChangeStPSP :=
intros s t Sub SP TF;  (* SUBJECT, Property and TransFunc *)
inversion TF; match goal with
| id:(s = t) |- _ => rewrite <- id; auto
end.
Ltac StartPSS := intros s t Sub SS TF; inversion TF.
Ltac BreakSS :=
match goal with
| SS:(SecureState _) |- _ =>
unfold SecureState in SS; elim SS; intros DAC MAC
end.
Ltac StartPSP := intros s t Sub SP TF; inversion TF.
unfold DACSecureState in |- *.
intros.
cut
match fsecmat (secmat s) o with
| Some y =>
(set_In u (ActReaders y) -> PreDACRead s u o) /\
(set_In u (ActWriters y) -> PreDACWrite s u o)
| None => True
end.
elim (fsecmat (secmat s) o).
intros.
elim H0; intros.
auto.
auto.
apply H.
Qed.
unfold DACSecureState in |- *.
intros.
cut
match fsecmat (secmat s) o with
| Some y =>
(set_In u (ActReaders y) -> PreDACRead s u o) /\
(set_In u (ActWriters y) -> PreDACWrite s u o)
| None => True
end.
elim (fsecmat (secmat s) o).
intros.
elim H0; intros.
auto.
auto.
apply H.
Qed.
intros.
cut (~ set_In u (ActReaders rw) /\ ~ set_In u (ActWriters rw)).
tauto.
auto.
Qed.

Lemma TwoImpRight :
forall (s : SFSstate) (u : SUBJECT),
(forall rw : ReadersWriters,
set_In rw (ransecmat (secmat s)) ->
~ set_In u (ActReaders rw) /\ ~ set_In u (ActWriters rw)) ->
forall rw : ReadersWriters,
set_In rw (ransecmat (secmat s)) -> ~ set_In u (ActWriters rw).