Require Import HaskProofToStrong.
Require Import HaskWeakToStrong.
+Require Import HaskSkolemizer.
+
Open Scope nd_scope.
Set Printing Width 130.
auto.
Qed.
+ Lemma take_lemma' : forall Γ (lev:HaskLevel Γ) x, take_lev lev (x @@@ lev) = x @@@ lev.
+ intros.
+ induction x.
+ destruct a; simpl; try reflexivity.
+ apply take_lemma.
+ simpl.
+ rewrite <- IHx1 at 2.
+ rewrite <- IHx2 at 2.
+ reflexivity.
+ Qed.
+(*
+ Lemma drop_lev_lemma' : forall Γ (lev:HaskLevel Γ) x, drop_lev lev (x @@@ lev) = [].
+ intros.
+ induction x.
+ destruct a; simpl; try reflexivity.
+ apply drop_lev_lemma.
+ simpl.
+ change (@drop_lev _ lev (x1 @@@ lev ,, x2 @@@ lev))
+ with ((@drop_lev _ lev (x1 @@@ lev)) ,, (@drop_lev _ lev (x2 @@@ lev))).
+ simpl.
+ rewrite IHx1.
+ rewrite IHx2.
+ reflexivity.
+ Qed.
+*)
Ltac drop_simplify :=
match goal with
| [ |- context[@drop_lev ?G ?L [ ?X @@ ?L ] ] ] =>
rewrite (drop_lev_lemma G L X)
+(*
+ | [ |- context[@drop_lev ?G ?L [ ?X @@@ ?L ] ] ] =>
+ rewrite (drop_lev_lemma' G L X)
+*)
| [ |- context[@drop_lev ?G (?E :: ?L) [ ?X @@ (?E :: ?L) ] ] ] =>
rewrite (drop_lev_lemma_s G L E X)
| [ |- context[@drop_lev ?G ?N (?A,,?B)] ] =>
match goal with
| [ |- context[@take_lev ?G ?L [ ?X @@ ?L ] ] ] =>
rewrite (take_lemma G L X)
+ | [ |- context[@take_lev ?G ?L [ ?X @@@ ?L ] ] ] =>
+ rewrite (take_lemma' G L X)
| [ |- context[@take_lev ?G ?N (?A,,?B)] ] =>
change (@take_lev G N (A,,B)) with ((@take_lev G N A),,(@take_lev G N B))
| [ |- context[@take_lev ?G ?N (T_Leaf None)] ] =>
Definition ga_mk_tree {Γ}(ec:HaskType Γ ECKind)(tr:Tree ??(HaskType Γ ★)) : HaskType Γ ★ :=
fun TV ite => ga_mk_tree' (ec TV ite) (mapOptionTree (fun x => x TV ite) tr).
- Definition ga_mk_raw {TV}(ec:RawHaskType TV ECKind )(ant suc:Tree ??(RawHaskType TV ★)) : RawHaskType TV ★ :=
- gaTy TV ec (ga_mk_tree' ec ant) (ga_mk_tree' ec suc).
+ Definition ga_mk_raw {TV}(ec:RawHaskType TV ECKind)(ant suc:Tree ??(RawHaskType TV ★)) : RawHaskType TV ★ :=
+ gaTy TV ec
+ (ga_mk_tree' ec ant)
+ (ga_mk_tree' ec suc).
- Definition ga_mk {Γ}(ec:HaskType Γ ECKind )(ant suc:Tree ??(HaskType Γ ★)) : HaskType Γ ★ :=
- fun TV ite => ga_mk_raw (ec TV ite) (mapOptionTree (fun x => x TV ite) ant) (mapOptionTree (fun x => x TV ite) suc).
+ Definition ga_mk {Γ}(ec:HaskType Γ ECKind)(ant suc:Tree ??(HaskType Γ ★)) : HaskType Γ ★ :=
+ fun TV ite => gaTy TV (ec TV ite) (ga_mk_tree ec ant TV ite) (ga_mk_tree ec suc TV ite).
(*
* The story:
| TCon tc => TCon tc
| TCoerc _ t1 t2 t => TCoerc (flatten_rawtype t1) (flatten_rawtype t2) (flatten_rawtype t)
| TArrow => TArrow
- | TCode ec e => ga_mk_raw ec [] [flatten_rawtype e]
+ | TCode ec e => let e' := flatten_rawtype e
+ in ga_mk_raw ec (unleaves_ (take_arg_types e')) [drop_arg_types e']
| TyFunApp tfc kl k lt => TyFunApp tfc kl k (flatten_rawtype_list _ lt)
end
with flatten_rawtype_list {TV}(lk:list Kind)(exp:@RawHaskTypeList TV lk) : @RawHaskTypeList TV lk :=
Fixpoint levels_to_tcode {Γ}(ht:HaskType Γ ★)(lev:HaskLevel Γ) : HaskType Γ ★ :=
match lev with
- | nil => ht
- | ec::lev' => fun TV ite => TCode (v2t ec TV ite) (levels_to_tcode ht lev' TV ite)
+ | nil => flatten_type ht
+ | ec::lev' => @ga_mk _ (v2t ec) [] [levels_to_tcode ht lev']
end.
Definition flatten_leveled_type {Γ}(ht:LeveledHaskType Γ ★) : LeveledHaskType Γ ★ :=
- flatten_type (levels_to_tcode (unlev ht) (getlev ht)) @@ nil.
+ levels_to_tcode (unlev ht) (getlev ht) @@ nil.
(* AXIOMS *)
apply ga_second.
Defined.
- Lemma ga_unkappa : ∀ Γ Δ ec l a b Σ,
+ Lemma ga_unkappa : ∀ Γ Δ ec l z a b Σ,
ND Rule
- [Γ > Δ > Σ |- [@ga_mk Γ ec a b @@ l] ]
- [Γ > Δ > Σ,,[@ga_mk Γ ec [] a @@ l] |- [@ga_mk Γ ec [] b @@ l] ].
+ [Γ > Δ > Σ |- [@ga_mk Γ ec a b @@ l] ]
+ [Γ > Δ > Σ,,[@ga_mk Γ ec z a @@ l] |- [@ga_mk Γ ec z b @@ l] ].
intros.
- set (ga_comp Γ Δ ec l [] a b) as q.
+ set (ga_comp Γ Δ ec l z a b) as q.
set (@RLet Γ Δ) as q'.
- set (@RLet Γ Δ [@ga_mk _ ec [] a @@ l] Σ (@ga_mk _ ec [] b) (@ga_mk _ ec a b) l) as q''.
+ set (@RLet Γ Δ [@ga_mk _ ec z a @@ l] Σ (@ga_mk _ ec z b) (@ga_mk _ ec a b) l) as q''.
eapply nd_comp.
Focus 2.
eapply nd_rule.
apply q.
Defined.
+ Lemma ga_unkappa' : ∀ Γ Δ ec l a b Σ x,
+ ND Rule
+ [Γ > Δ > Σ |- [@ga_mk Γ ec (a,,x) b @@ l] ]
+ [Γ > Δ > Σ,,[@ga_mk Γ ec [] a @@ l] |- [@ga_mk Γ ec x b @@ l] ].
+ intros.
+ eapply nd_comp; [ idtac | eapply nd_rule; eapply RLet ].
+ eapply nd_comp; [ apply nd_llecnac | idtac ].
+ apply nd_prod.
+ apply ga_first.
+
+ eapply nd_comp; [ idtac | eapply nd_rule; eapply RLet ].
+ eapply nd_comp; [ apply nd_llecnac | idtac ].
+ apply nd_prod.
+ apply postcompose.
+ apply ga_uncancell.
+ apply precompose.
+ Defined.
+
+ Lemma ga_kappa' : ∀ Γ Δ ec l a b Σ x,
+ ND Rule
+ [Γ > Δ > Σ,,[@ga_mk Γ ec [] a @@ l] |- [@ga_mk Γ ec x b @@ l] ]
+ [Γ > Δ > Σ |- [@ga_mk Γ ec (a,,x) b @@ l] ].
+ apply (Prelude_error "ga_kappa not supported yet (BIG FIXME)").
+ Defined.
+
(* useful for cutting down on the pretty-printed noise
Notation "` x" := (take_lev _ x) (at level 20).
(mapOptionTree (flatten_type ○ unlev) (take_lev (ec :: lev) B))
(mapOptionTree (flatten_type ○ unlev) (take_lev (ec :: lev) A)) @@ nil]]
with
+ | RId a => let case_RId := tt in ga_id _ _ _ _ _
| RCanL a => let case_RCanL := tt in ga_uncancell _ _ _ _ _
| RCanR a => let case_RCanR := tt in ga_uncancelr _ _ _ _ _
| RuCanL a => let case_RuCanL := tt in ga_cancell _ _ _ _ _
match r as R in Arrange A B return
Arrange (mapOptionTree (flatten_leveled_type ) (drop_lev _ A))
(mapOptionTree (flatten_leveled_type ) (drop_lev _ B)) with
+ | RId a => let case_RId := tt in RId _
| RCanL a => let case_RCanL := tt in RCanL _
| RCanR a => let case_RCanR := tt in RCanR _
| RuCanL a => let case_RuCanL := tt in RuCanL _
apply nd_rule.
apply RArrange.
induction r; simpl.
+ apply RId.
apply RCanL.
apply RCanR.
apply RuCanL.
Definition arrange_brak : forall Γ Δ ec succ t,
ND Rule
[Γ > Δ > mapOptionTree (flatten_leveled_type ) (drop_lev (ec :: nil) succ),,
- [(@ga_mk _ (v2t ec) []
- (mapOptionTree (flatten_type ○ unlev) (take_lev (ec :: nil) succ)))
- @@ nil] |- [(@ga_mk _ (v2t ec) [] [flatten_type t]) @@ nil]]
- [Γ > Δ > mapOptionTree (flatten_leveled_type ) succ |- [(@ga_mk _ (v2t ec) [] [flatten_type t]) @@ nil]].
+ [(@ga_mk _ (v2t ec) [] (mapOptionTree (flatten_type ○ unlev) (take_lev (ec :: nil) succ))) @@ nil] |- [t @@ nil]]
+ [Γ > Δ > mapOptionTree (flatten_leveled_type ) succ |- [t @@ nil]].
intros.
unfold drop_lev.
set (@arrange' _ succ (levelMatch (ec::nil))) as q.
unfold flatten_leveled_type.
simpl.
unfold flatten_type.
+ simpl.
+ unfold ga_mk.
+ simpl.
apply RVar.
simpl.
apply ga_id.
apply IHsucc2.
Defined.
+ Definition arrange_empty_tree : forall {T}{A}(q:Tree A)(t:Tree ??T),
+ t = mapTree (fun _:A => None) q ->
+ Arrange t [].
+ intros T A q.
+ induction q; intros.
+ simpl in H.
+ rewrite H.
+ apply RId.
+ simpl in *.
+ destruct t; try destruct o; inversion H.
+ set (IHq1 _ H1) as x1.
+ set (IHq2 _ H2) as x2.
+ eapply RComp.
+ eapply RRight.
+ rewrite <- H1.
+ apply x1.
+ eapply RComp.
+ apply RCanL.
+ rewrite <- H2.
+ apply x2.
+ Defined.
+
+(* Definition unarrange_empty_tree : forall {T}{A}(t:Tree ??T)(q:Tree A),
+ t = mapTree (fun _:A => None) q ->
+ Arrange [] t.
+ Defined.*)
+
+ Definition decide_tree_empty : forall {T:Type}(t:Tree ??T),
+ sum { q:Tree unit & t = mapTree (fun _ => None) q } unit.
+ intro T.
+ refine (fix foo t :=
+ match t with
+ | T_Leaf x => _
+ | T_Branch b1 b2 => let b1' := foo b1 in let b2' := foo b2 in _
+ end).
+ intros.
+ destruct x.
+ right; apply tt.
+ left.
+ exists (T_Leaf tt).
+ auto.
+ destruct b1'.
+ destruct b2'.
+ destruct s.
+ destruct s0.
+ subst.
+ left.
+ exists (x,,x0).
+ reflexivity.
+ right; auto.
+ right; auto.
+ Defined.
+
Definition arrange_esc : forall Γ Δ ec succ t,
ND Rule
- [Γ > Δ > mapOptionTree (flatten_leveled_type ) succ |- [(@ga_mk _ (v2t ec) [] [flatten_type t]) @@ nil]]
+ [Γ > Δ > mapOptionTree (flatten_leveled_type ) succ |- [t @@ nil]]
[Γ > Δ > mapOptionTree (flatten_leveled_type ) (drop_lev (ec :: nil) succ),,
- [(@ga_mk _ (v2t ec) []
- (mapOptionTree (flatten_type ○ unlev) (take_lev (ec :: nil) succ))) @@ nil]
- |- [(@ga_mk _ (v2t ec) [] [flatten_type t]) @@ nil]].
+ [(@ga_mk _ (v2t ec) [] (mapOptionTree (flatten_type ○ unlev) (take_lev (ec :: nil) succ))) @@ nil] |- [t @@ nil]].
intros.
- unfold drop_lev.
set (@arrange _ succ (levelMatch (ec::nil))) as q.
+ set (@drop_lev Γ (ec::nil) succ) as q'.
+ assert (@drop_lev Γ (ec::nil) succ=q') as H.
+ reflexivity.
+ unfold drop_lev in H.
+ unfold mkDropFlags in H.
+ rewrite H in q.
+ clear H.
set (arrangeMap _ _ flatten_leveled_type q) as y.
eapply nd_comp.
eapply nd_rule.
eapply RArrange.
apply y.
- idtac.
clear y q.
+ set (mapOptionTree flatten_leveled_type (dropT (mkFlags (liftBoolFunc false (bnot ○ levelMatch (ec :: nil))) succ))) as q.
+ destruct (decide_tree_empty q); [ idtac | apply (Prelude_error "escapifying open code not yet supported") ].
+ destruct s.
+
+ simpl.
+ eapply nd_comp; [ idtac | eapply nd_rule; eapply RArrange; apply RExch ].
+ set (fun z z' => @RLet Γ Δ z (mapOptionTree flatten_leveled_type q') t z' nil) as q''.
+ eapply nd_comp; [ idtac | eapply nd_rule; apply q'' ].
+ clear q''.
+ eapply nd_comp; [ apply nd_rlecnac | idtac ].
+ apply nd_prod.
+ apply nd_rule.
+ apply RArrange.
+ eapply RComp; [ idtac | apply RCanR ].
+ apply RLeft.
+ apply (@arrange_empty_tree _ _ _ _ e).
+
+ eapply nd_comp.
+ eapply nd_rule.
+ eapply (@RVar Γ Δ t nil).
+ apply nd_rule.
+ apply RArrange.
+ eapply RComp.
+ apply RuCanL.
+ apply RRight.
+ apply RWeak.
+(*
+ eapply decide_tree_empty.
+
+ simpl.
+ set (dropT (mkFlags (liftBoolFunc false (bnot ○ levelMatch (ec :: nil))) succ)) as escapified.
+ destruct (decide_tree_empty escapified).
+
induction succ.
destruct a.
+ unfold drop_lev.
destruct l.
simpl.
unfold mkDropFlags; simpl.
apply RLeft.
apply RWeak.
apply (Prelude_error "escapifying code with multi-leaf antecedents is not supported").
+*)
Defined.
Lemma mapOptionTree_distributes
reflexivity.
Qed.
- Definition decide_tree_empty : forall {T:Type}(t:Tree ??T),
- sum { q:Tree unit & t = mapTree (fun _ => None) q } unit.
- intro T.
- refine (fix foo t :=
- match t with
- | T_Leaf x => _
- | T_Branch b1 b2 => let b1' := foo b1 in let b2' := foo b2 in _
- end).
+ Lemma unlev_relev : forall {Γ}(t:Tree ??(HaskType Γ ★)) lev, mapOptionTree unlev (t @@@ lev) = t.
intros.
- destruct x.
- right; apply tt.
- left.
- exists (T_Leaf tt).
- auto.
- destruct b1'.
- destruct b2'.
- destruct s.
- destruct s0.
- subst.
- left.
- exists (x,,x0).
+ induction t.
+ destruct a; reflexivity.
+ rewrite <- IHt1 at 2.
+ rewrite <- IHt2 at 2.
reflexivity.
- right; auto.
- right; auto.
+ Qed.
+
+ Lemma tree_of_nothing : forall Γ ec t a,
+ Arrange (a,,mapOptionTree flatten_leveled_type (drop_lev(Γ:=Γ) (ec :: nil) (t @@@ (ec :: nil)))) a.
+ intros.
+ induction t; try destruct o; try destruct a0.
+ simpl.
+ drop_simplify.
+ simpl.
+ apply RCanR.
+ simpl.
+ apply RCanR.
+ Opaque drop_lev.
+ simpl.
+ Transparent drop_lev.
+ drop_simplify.
+ simpl.
+ eapply RComp.
+ eapply RComp.
+ eapply RAssoc.
+ eapply RRight.
+ apply IHt1.
+ apply IHt2.
Defined.
+ Lemma tree_of_nothing' : forall Γ ec t a,
+ Arrange a (a,,mapOptionTree flatten_leveled_type (drop_lev(Γ:=Γ) (ec :: nil) (t @@@ (ec :: nil)))).
+ intros.
+ induction t; try destruct o; try destruct a0.
+ simpl.
+ drop_simplify.
+ simpl.
+ apply RuCanR.
+ simpl.
+ apply RuCanR.
+ Opaque drop_lev.
+ simpl.
+ Transparent drop_lev.
+ drop_simplify.
+ simpl.
+ eapply RComp.
+ Focus 2.
+ eapply RComp.
+ Focus 2.
+ eapply RCossa.
+ Focus 2.
+ eapply RRight.
+ apply IHt1.
+ apply IHt2.
+ Defined.
+
+ Lemma krunk : forall Γ (ec:HaskTyVar Γ ECKind) t,
+ flatten_type (<[ ec |- t ]>)
+ = @ga_mk Γ (v2t ec)
+ (mapOptionTree flatten_type (take_arg_types_as_tree t))
+ [ flatten_type (drop_arg_types_as_tree t)].
+ intros.
+ unfold flatten_type at 1.
+ simpl.
+ unfold ga_mk.
+ apply phoas_extensionality.
+ intros.
+ unfold v2t.
+ unfold ga_mk_raw.
+ unfold ga_mk_tree.
+ rewrite <- mapOptionTree_compose.
+ unfold take_arg_types_as_tree.
+ simpl.
+ replace (flatten_type (drop_arg_types_as_tree t) tv ite)
+ with (drop_arg_types (flatten_rawtype (t tv ite))).
+ replace (unleaves_ (take_arg_types (flatten_rawtype (t tv ite))))
+ with ((mapOptionTree (fun x : HaskType Γ ★ => flatten_type x tv ite)
+ (unleaves_
+ (take_trustme (count_arg_types (t (fun _ : Kind => unit) (ite_unit Γ)))
+ (fun TV : Kind → Type => take_arg_types ○ t TV))))).
+ reflexivity.
+ unfold flatten_type.
+ clear hetmet_flatten.
+ clear hetmet_unflatten.
+ clear hetmet_id.
+ clear gar.
+ set (t tv ite) as x.
+ admit.
+ admit.
+ Qed.
+
Definition flatten_proof :
forall {h}{c},
- ND Rule h c ->
- ND Rule (mapOptionTree (flatten_judgment ) h) (mapOptionTree (flatten_judgment ) c).
+ ND SRule h c ->
+ ND Rule (mapOptionTree (flatten_judgment ) h) (mapOptionTree (flatten_judgment ) c).
intros.
eapply nd_map'; [ idtac | apply X ].
clear h c X.
intros.
simpl in *.
- refine (match X as R in Rule H C with
+ refine
+ (match X as R in SRule H C with
+ | SBrak Γ Δ t ec succ lev => let case_SBrak := tt in _
+ | SEsc Γ Δ t ec succ lev => let case_SEsc := tt in _
+ | SFlat h c r => let case_SFlat := tt in _
+ end).
+
+ destruct case_SFlat.
+ refine (match r as R in Rule H C with
| RArrange Γ Δ a b x d => let case_RArrange := tt in _
| RNote Γ Δ Σ τ l n => let case_RNote := tt in _
| RLit Γ Δ l _ => let case_RLit := tt in _
apply (flatten_arrangement'' Γ Δ a b x d).
destruct case_RBrak.
- simpl.
- destruct lev.
- change ([flatten_type (<[ ec |- t ]>) @@ nil])
- with ([ga_mk (v2t ec) [] [flatten_type t] @@ nil]).
- refine (ga_unkappa Γ Δ (v2t ec) nil (mapOptionTree (flatten_type ○ unlev) (take_lev (ec::nil) succ)) _
- (mapOptionTree (flatten_leveled_type) (drop_lev (ec::nil) succ)) ;; _ ).
- apply arrange_brak.
- apply (Prelude_error "found Brak at depth >0 indicating 3-level code; only two-level code is currently supported").
+ apply (Prelude_error "found unskolemized Brak rule; this shouldn't happen").
destruct case_REsc.
- simpl.
- destruct lev.
- simpl.
- change ([flatten_leveled_type (<[ ec |- t ]> @@ nil)])
- with ([ga_mk (v2t ec) [] [flatten_type t] @@ nil]).
- eapply nd_comp; [ apply arrange_esc | idtac ].
- set (decide_tree_empty (take_lev (ec :: nil) succ)) as q'.
- destruct q'.
- destruct s.
- rewrite e.
- clear e.
-
- eapply nd_comp; [ idtac | eapply nd_rule; eapply RArrange; eapply RCanR ].
- eapply nd_comp; [ idtac | eapply nd_rule; eapply RLet ].
- eapply nd_comp; [ apply nd_llecnac | idtac ].
- apply nd_prod; [ idtac | eapply boost ].
- induction x.
- apply ga_id.
- eapply nd_comp; [ idtac | eapply nd_rule; eapply RArrange; eapply RCanR ].
- simpl.
- apply ga_join.
- apply IHx1.
- apply IHx2.
- simpl.
- apply postcompose.
- apply ga_drop.
-
- (* environment has non-empty leaves *)
- apply (ga_kappa Γ Δ (v2t ec) nil (mapOptionTree (flatten_type ○ unlev) (take_lev (ec::nil) succ)) _ _).
- apply (Prelude_error "found Esc at depth >0 indicating 3-level code; only two-level code is currently supported").
+ apply (Prelude_error "found unskolemized Esc rule; this shouldn't happen").
destruct case_RNote.
simpl.
destruct case_RCast.
simpl.
destruct lev as [|ec lev]; simpl; [ apply nd_rule; apply RCast; auto | idtac ].
+ simpl.
apply flatten_coercion; auto.
apply (Prelude_error "RCast at level >0; casting inside of code brackets is currently not supported").
destruct case_RCase.
simpl.
apply (Prelude_error "Case not supported (BIG FIXME)").
+
+ destruct case_SBrak.
+ simpl.
+ destruct lev.
+ drop_simplify.
+ set (drop_lev (ec :: nil) (take_arg_types_as_tree t @@@ (ec :: nil))) as empty_tree.
+ take_simplify.
+ rewrite take_lemma'.
+ simpl.
+ rewrite mapOptionTree_compose.
+ rewrite mapOptionTree_compose.
+ rewrite unlev_relev.
+ rewrite <- mapOptionTree_compose.
+ unfold flatten_leveled_type at 4.
+ simpl.
+ rewrite krunk.
+ set (mapOptionTree flatten_leveled_type (drop_lev (ec :: nil) succ)) as succ_host.
+ set (mapOptionTree (flatten_type ○ unlev)(take_lev (ec :: nil) succ)) as succ_guest.
+ set (mapOptionTree flatten_type (take_arg_types_as_tree t)) as succ_args.
+ unfold empty_tree.
+ eapply nd_comp; [ eapply nd_rule; eapply RArrange; apply tree_of_nothing | idtac ].
+ refine (ga_unkappa' Γ Δ (v2t ec) nil _ _ _ _ ;; _).
+ unfold succ_host.
+ unfold succ_guest.
+ apply arrange_brak.
+ apply (Prelude_error "found Brak at depth >0 indicating 3-level code; only two-level code is currently supported").
+
+ destruct case_SEsc.
+ simpl.
+ destruct lev.
+ simpl.
+ unfold flatten_leveled_type at 2.
+ simpl.
+ rewrite krunk.
+ rewrite mapOptionTree_compose.
+ take_simplify.
+ drop_simplify.
+ simpl.
+ eapply nd_comp; [ idtac | eapply nd_rule; eapply RArrange; apply tree_of_nothing' ].
+ simpl.
+ rewrite take_lemma'.
+ rewrite unlev_relev.
+ rewrite <- mapOptionTree_compose.
+ eapply nd_comp; [ apply (arrange_esc _ _ ec) | idtac ].
+
+ set (decide_tree_empty (take_lev (ec :: nil) succ)) as q'.
+ destruct q'.
+ destruct s.
+ rewrite e.
+ clear e.
+
+ set (mapOptionTree flatten_leveled_type (drop_lev (ec :: nil) succ)) as succ_host.
+ set (mapOptionTree flatten_type (take_arg_types_as_tree t)) as succ_args.
+
+ eapply nd_comp; [ idtac | eapply nd_rule; eapply RArrange; apply RCanR ].
+ eapply nd_comp; [ idtac | eapply nd_rule; eapply RLet ].
+ eapply nd_comp; [ apply nd_llecnac | idtac ].
+ apply nd_prod; [ idtac | eapply boost ].
+ induction x.
+ apply ga_id.
+ eapply nd_comp; [ idtac | eapply nd_rule; eapply RArrange; eapply RCanR ].
+ simpl.
+ apply ga_join.
+ apply IHx1.
+ apply IHx2.
+ simpl.
+ apply postcompose.
+
+ refine ( _ ;; (boost _ _ _ _ _ (postcompose _ _ _ _ _ _ _ _))).
+ apply ga_cancell.
+ apply firstify.
+
+ induction x.
+ destruct a; simpl.
+ apply ga_id.
+ simpl.
+ refine ( _ ;; (boost _ _ _ _ _ (postcompose _ _ _ _ _ _ _ _))).
+ apply ga_cancell.
+ refine ( _ ;; (boost _ _ _ _ _ (postcompose _ _ _ _ _ _ _ _))).
+ eapply firstify.
+ apply IHx1.
+ apply secondify.
+ apply IHx2.
+
+ (* environment has non-empty leaves *)
+ apply ga_kappa'.
+
+ (* nesting too deep *)
+ apply (Prelude_error "found Esc at depth >0 indicating 3-level code; only two-level code is currently supported").
Defined.
+ Definition skolemize_and_flatten_proof :
+ forall {h}{c},
+ ND Rule h c ->
+ ND Rule
+ (mapOptionTree (flatten_judgment ○ skolemize_judgment) h)
+ (mapOptionTree (flatten_judgment ○ skolemize_judgment) c).
+ intros.
+ rewrite mapOptionTree_compose.
+ rewrite mapOptionTree_compose.
+ apply flatten_proof.
+ apply skolemize_proof.
+ apply X.
+ Defined.
+
(* to do: establish some metric on judgments (max length of level of any succedent type, probably), show how to
* calculate it, and show that the flattening procedure above drives it down by one *)