(* File: NWeight.v  (last edited on 27/10/2000) (c) Klaus Weich  *)
Require Export Lt.
Require Export Le.
Require Export Regular_Avl.
Require Export Le_Ks.
(*********************************************************************)
Fixpoint nweight (a : form) : nat :=
match a with
| Atom _ => 0
| Falsum => 0
| AndF a0 a1 => S (nweight a0 + nweight a1)
| OrF a0 a1 => S (nweight a0 + nweight a1)
| Imp a0 a1 => S (nweight a0 + nweight a1)
end.
(******************************************************************)
Definition nweight_work :=
fold_right (fun (a : normal_form) (n : nat) => nweight (nf2form a) + n) 0.
Remark nweight_work_app :
forall bs work : nf_list,
nweight_work (bs ++ work) = nweight_work bs + nweight_work work.
intros bs work; elim bs; clear bs.
simpl in |- *; trivial.
intros b bs ih.
unfold nweight_work in |- *.
simpl in |- *.
fold nweight_work in |- *.
rewrite ih.
apply plus_assoc.
Qed.
Definition nweight_disj (d : disj) := nweight (disj2form d).
Definition nweight_ds :=
fold_right (fun (d : disj) (n : nat) => nweight_disj d + n) 0.
Definition nweight_nestedimp (x : nested_imp) := nweight (nested_imp2form x).
Definition nweight_ni :=
fold_right (fun (x : nested_imp) (n : nat) => nweight_nestedimp x + n) 0.
Definition nweight_decoratednestedimp (x : decorated_nested_imp) :=
match x with
| (x0, _) => nweight (nimp2form x0)
end.
Definition nweight_dni :=
fold_right
(fun (x : decorated_nested_imp) (n : nat) =>
nweight_decoratednestedimp x + n) 0.
Definition nweight_atomicimp (a : normal_form) := S (nweight (nf2form a)).
Definition nweight_bs :=
fold_right (fun (b : normal_form) (n : nat) => nweight_atomicimp b + n) 0.
Definition nweight_ibs (x : Int * nf_list) :=
match x with
| (_, bs) => nweight_bs bs
end.
Definition nweight_ai (ai : atomic_imps) :=
fold_right (fun (x : Int * nf_list) (n : nat) => nweight_ibs x + n) 0
(LIN_AVL nf_list ai).
(***************************************************************************)
Remark nweight_ai_perm :
forall (l0 l1 : list (Int * nf_list)) (x : Int * nf_list),
fold_right (fun (x : Int * nf_list) (n : nat) => nweight_ibs x + n) 0
(l0 ++ x :: l1) =
fold_right (fun (x : Int * nf_list) (n : nat) => nweight_ibs x + n) 0
(x :: l0 ++ l1).
intros l0 l1 x.
apply fold_right_perm.
intros.
apply plus_permute.
Qed.
Remark nweight_ai_ins :
forall (i : Int) (b : normal_form) (ai ai' : atomic_imps),
LIN_INS nf_list i (cons b) nf_nil ai ai' ->
nweight (nf2form (AImp i b)) + nweight_ai ai = nweight_ai ai'.
intros i b ai ai'.
elim ai; clear ai.
elim ai'; clear ai'.
intros t' avl_t' t avl_t.
simpl in |- *.
intro lin_ins.
unfold nweight_ai in |- *.
unfold LIN_AVL in |- *.
clear avl_t' avl_t.
inversion_clear lin_ins.
rewrite H.
rewrite H0.
clear H H0.
transitivity
(fold_right (fun (x : Int * nf_list) (n : nat) => nweight_ibs x + n) 0
((i, b :: nf_nil) :: l0 ++ l1)).
simpl in |- *.
rewrite (plus_O (nweight (nf2form b))).
trivial.
symmetry  in |- *.
apply nweight_ai_perm.
rewrite H.
rewrite H0.
clear H H0.
transitivity
(fold_right (fun (x : Int * nf_list) (n : nat) => nweight_ibs x + n) 0
((i, b :: d) :: l0 ++ l1)).
change
(S
(nweight (nf2form b) +
fold_right (fun (x : Int * nf_list) (n : nat) => nweight_ibs x + n) 0
(l0 ++ (i, d) :: l1)) =
S
(nweight (nf2form b) + nweight_bs d +
fold_right (fun (x : Int * nf_list) (n : nat) => nweight_ibs x + n) 0
(l0 ++ l1))) in |- *.
apply S_reg.
generalize (nweight (nf2form b)); clear b; intro b.
rewrite
(plus_assoc_reverse b (nweight_bs d)
(fold_right (fun (x : Int * nf_list) (n : nat) => nweight_ibs x + n) 0
(l0 ++ l1))).
apply plus_reg.
change
(fold_right (fun (x : Int * nf_list) (n : nat) => nweight_ibs x + n) 0
(l0 ++ (i, d) :: l1) =
fold_right (fun (x : Int * nf_list) (n : nat) => nweight_ibs x + n) 0
((i, d) :: l0 ++ l1)) in |- *.
apply nweight_ai_perm.
symmetry  in |- *.
apply nweight_ai_perm.
Qed.
Remark nweight_ai_del :
forall (i : Int) (bs : nf_list) (ai ai' : atomic_imps),
REGULAR normal_form ai ->
LOOKUP nf_list i ai bs ->
LIN_DEL nf_list i bs ai ai' ->
nweight_work bs + nweight_ai ai' < nweight_ai ai.
intros i bs ai ai'.
elim ai; clear ai; intros t avl_t.
elim ai'; clear ai'; intros t' avl_t'.
simpl in |- *.
intros reg_t lookup lin_del.
unfold nweight_ai in |- *.
inversion_clear lin_del.
simpl in |- *.
rewrite H; clear H.
rewrite H0; clear H0.
rewrite (nweight_ai_perm l0 l1 (i, bs)).
simpl in |- *.
apply plus_lt_compat_r.
generalize (reg_t i bs lookup); clear reg_t lookup.
case bs; clear bs.
intros H; elimtype False.
apply H; trivial.
intros b bs H.
unfold lt in |- *.
unfold nweight_work in |- *.
unfold nweight_bs in |- *.
simpl in |- *.
apply le_n_S.
apply plus_le_compat_l.
elim bs; clear H bs.
simpl in |- *.
apply le_O_n.
intros b0 bs ih.
simpl in |- *.
change
(nweight (nf2form b0) +
fold_right (fun (a : normal_form) (n : nat) => nweight (nf2form a) + n) 0
bs <=
S (nweight (nf2form b0)) +
fold_right
(fun (b : normal_form) (n : nat) => S (nweight (nf2form b) + n)) 0 bs)
in |- *.
apply plus_le_compat.
apply le_n_Sn.
assumption.
Qed.
(*********************************************************************)
Remark nweight_eqv_ni :
forall ni1 ni2 : nested_imps,
eqv_ni ni1 ni2 -> nweight_ni ni1 = nweight_ni ni2.
intros ni1 ni2 eqv12.
elim eqv12; clear eqv12 ni1 ni2.
trivial.
intros x ni1 ni2 eqv12 ih.
unfold nweight_ni in |- *.
simpl in |- *.
fold nweight_ni in |- *.
rewrite ih; trivial.
intros x k ni1 ni2 eqv12 ih.
unfold nweight_ni in |- *.
simpl in |- *.
fold nweight_ni in |- *.
rewrite ih; trivial.
intros x k k' ni1 ni2 eqv12 ih.
unfold nweight_ni in |- *.
simpl in |- *.
fold nweight_ni in |- *.
rewrite ih; trivial.
intros x k ni1 ni2 eqv12 ih.
unfold nweight_ni in |- *.
simpl in |- *.
fold nweight_ni in |- *.
rewrite ih; trivial.
Qed.
Remark nweight_rev_app :
forall (dni : decorated_nested_imps) (ni : nested_imps),
nweight_ni ni + nweight_dni dni = nweight_ni (rev_app dni ni).
intros dni; elim dni; clear dni.
intros ni; unfold nweight_dni in |- *; simpl in |- *.
apply plus_O.
intros x dni ih ni.
case x; clear x.
intros n k.
simpl in |- *.
rewrite <- (ih (Decorated n k :: ni)); clear ih.
unfold nweight_ni in |- *; simpl in |- *; fold nweight_ni in |- *.
unfold nweight_nestedimp in |- *.
unfold nested_imp2form in |- *.
simpl in |- *.
generalize (nweight (nimp2form n)); clear n; intros n.
generalize (nweight_ni ni); clear ni; intros ni.
generalize (nweight_dni dni); clear dni; intros dni.
rewrite (plus_assoc ni n dni).
rewrite (plus_comm ni n).
trivial.
Qed.
(**********************************************************************)
Definition nweight_Sequent (work : nf_list) (ds : disjs)
(ni : nested_imps) (ai : atomic_imps) :=
nweight_work work + (nweight_ds ds + (nweight_ni ni + nweight_ai ai)).
intros x work ds ni ai.
unfold nweight_Sequent in |- *.
simpl in |- *.
fold nimp2form in |- *.
generalize (nweight_ai ai); clear ai; intro ai.
generalize (nweight_ds ds); clear ds; intro ds.
generalize (nweight_work work); clear work; intro W.
generalize (nweight_ni ni); clear ni; intros ni.
change
(nweight (nimp2form x) + W + (ds + (ni + ai)) =
W + (ds + (nweight (nimp2form x) + ni + ai))) in |- *.
generalize (nweight (nimp2form x)); clear x; intro x.
rewrite (plus_comm x W).
rewrite (plus_assoc_reverse W x (ds + (ni + ai))).
apply plus_reg.
rewrite (plus_assoc x ds (ni + ai)).
rewrite (plus_comm x ds).
rewrite (plus_assoc_reverse ds x (ni + ai)).
apply plus_reg.
apply plus_assoc.
Qed.
intros i j work ds ni ai.
unfold nweight_Sequent in |- *.
generalize (nweight_ni ni + nweight_ai ai).
clear ni ai; intros n.
simpl in |- *.
fold nweight_work in |- *.
fold nweight_ds in |- *.
rewrite <- (plus_Snm_nSm (nweight_work work) (nweight_ds ds + n)).
trivial.
Qed.
intros.
unfold nweight_Sequent in |- *.
rewrite <- (nweight_ai_ins i b ai ai').
generalize (nweight_ai ai); clear H ai ai'; intro ai.
generalize (nweight_ds ds); clear ds; intro ds.
generalize (nweight_ni ni); clear ni; intro ni.
change
(nweight (nf2form (AImp i b)) + nweight_work work + (ds + (ni + ai)) =
nweight_work work + (ds + (ni + (nweight (nf2form (AImp i b)) + ai))))
in |- *.
generalize (nweight_work work); clear work; intro work.
generalize (nweight (nf2form (AImp i b))); clear i b; intro a.
rewrite (plus_comm a work).
rewrite (plus_assoc_reverse work a (ds + (ni + ai))).
apply plus_reg.
rewrite (plus_permute a ds (ni + ai)).
apply plus_reg.
rewrite (plus_permute a ni ai).
apply plus_reg.
trivial.
assumption.
Qed.
(*******************************************************************)

Lemma nweight_shift_ai_work :
forall (i : Int) (bs work : nf_list) (ds : disjs)
(ni : nested_imps) (ai ai' : atomic_imps),
LOOKUP nf_list i ai bs ->
REGULAR normal_form ai ->
LIN_DEL nf_list i bs ai ai' ->
nweight_Sequent (bs ++ work) ds ni ai' < nweight_Sequent work ds ni ai.