(*********************************************************************************************************************************)
-(* NaturalDeduction: *)
+(* ProgrammingLanguage *)
(* *)
-(* Structurally explicit natural deduction proofs. *)
+(* Basic assumptions about programming languages. *)
(* *)
(*********************************************************************************************************************************)
Require Import Preamble.
Require Import General.
Require Import Categories_ch1_3.
+Require Import InitialTerminal_ch2_2.
Require Import Functors_ch1_4.
Require Import Isomorphisms_ch1_5.
Require Import ProductCategories_ch1_6_1.
Require Import Subcategories_ch7_1.
Require Import NaturalTransformations_ch7_4.
Require Import NaturalIsomorphisms_ch7_5.
+Require Import BinoidalCategories.
+Require Import PreMonoidalCategories.
Require Import MonoidalCategories_ch7_8.
Require Import Coherence_ch7_8.
Require Import Enrichment_ch2_8.
Require Import RepresentableStructure_ch7_2.
-Require Import NaturalDeduction.
+Require Import FunctorCategories_ch7_7.
+Require Import NaturalDeduction.
-(*
- * Everything in the rest of this section is just groundwork meant to
- * build up to the definition of the AcceptableLanguage class, which
- * appears at the end of the section. References to "the instance"
- * mean instances of that class. Think of this section as being one
- * big Class { ... } definition, except that we declare most of the
- * stuff outside the curly brackets in order to take advantage of
- * Coq's section mechanism.
- *)
-Section Acceptable_Language.
+Section Programming_Language.
- (* Formalized Definition 4.1.1, production $\tau$ *)
Context {T : Type}. (* types of the language *)
- Inductive Sequent := sequent : Tree ??T -> Tree ??T -> Sequent.
- Notation "cs |= ss" := (sequent cs ss) : al_scope.
- (* Because of term irrelevance we need only store the *erased* (def
- * 4.4) trees; for this reason there is no Coq type directly
- * corresponding to productions $e$ and $x$ of 4.1.1, and TreeOT can
- * be used for productions $\Gamma$ and $\Sigma$ *)
-
- (* to do: sequent calculus equals natural deduction over sequents, theorem equals sequent with null antecedent, *)
+ Definition PLJudg := (Tree ??T) * (Tree ??T).
+ Definition sequent := @pair (Tree ??T) (Tree ??T).
+ Notation "cs |= ss" := (sequent cs ss) : pl_scope.
- Context {Rule : Tree ??Sequent -> Tree ??Sequent -> Type}.
+ Context {Rule : Tree ??PLJudg -> Tree ??PLJudg -> Type}.
- Notation "H /⋯⋯/ C" := (ND Rule H C) : al_scope.
+ Notation "H /⋯⋯/ C" := (ND Rule H C) : pl_scope.
Open Scope pf_scope.
Open Scope nd_scope.
- Open Scope al_scope.
-
- (* Formalized Definition 4.1
- *
- * Note that from this abstract interface, the terms (expressions)
- * in the proof are not accessible at all; they don't need to be --
- * so long as we have access to the equivalence relation upon
- * proof-conclusions. Moreover, hiding the expressions actually
- * makes the encoding in CiC work out easier for two reasons:
- *
- * 1. Because the denotation function is provided a proof rather
- * than a term, it is a total function (the denotation function is
- * often undefined for ill-typed terms).
- *
- * 2. We can define arr_composition of proofs without having to know how
- * to compose expressions. The latter task is left up to the client
- * function which extracts an expression from a completed proof.
- *
- * This also means that we don't need an explicit proof obligation for 4.1.2.
- *)
- Class AcceptableLanguage :=
-
- (* Formalized Definition 4.1: denotational semantics equivalence relation on the conclusions of proofs *)
- { al_eqv : @ND_Relation Sequent Rule
- where "pf1 === pf2" := (@ndr_eqv _ _ al_eqv _ _ pf1 pf2)
-
- (* Formalized Definition 4.1.3; note that t here is either $\top$ or a single type, not a Tree of types;
- * we rely on "completeness of atomic initial segments" (http://en.wikipedia.org/wiki/Completeness_of_atomic_initial_sequents)
- * to generate the rest *)
- ; al_reflexive_seq : forall t, Rule [] [t|=t]
-
- (* these can all be absorbed into a separate "sequent calculus" presentation *)
- ; al_ant_assoc : forall {a b c d}, Rule [(a,,b),,c|=d] [(a,,(b,,c))|=d]
- ; al_ant_cossa : forall {a b c d}, Rule [a,,(b,,c)|=d] [((a,,b),,c)|=d]
- ; al_ant_cancell : forall {a b }, Rule [ [],,a |=b] [ a |=b]
- ; al_ant_cancelr : forall {a b }, Rule [a,,[] |=b] [ a |=b]
- ; al_ant_llecnac : forall {a b }, Rule [ a |=b] [ [],,a |=b]
- ; al_ant_rlecnac : forall {a b }, Rule [ a |=b] [ a,,[] |=b]
- ; al_suc_assoc : forall {a b c d}, Rule [d|=(a,,b),,c] [d|=(a,,(b,,c))]
- ; al_suc_cossa : forall {a b c d}, Rule [d|=a,,(b,,c)] [d|=((a,,b),,c)]
- ; al_suc_cancell : forall {a b }, Rule [a|=[],,b ] [a|= b ]
- ; al_suc_cancelr : forall {a b }, Rule [a|=b,,[] ] [a|= b ]
- ; al_suc_llecnac : forall {a b }, Rule [a|= b ] [a|=[],,b ]
- ; al_suc_rlecnac : forall {a b }, Rule [a|= b ] [a|=b,,[] ]
-
- ; al_horiz_expand_left : forall tau {Gamma Sigma}, Rule [ Gamma |= Sigma ] [tau,,Gamma|=tau,,Sigma]
- ; al_horiz_expand_right : forall tau {Gamma Sigma}, Rule [ Gamma |= Sigma ] [Gamma,,tau|=Sigma,,tau]
-
- (* these are essentially one way of formalizing
- * "completeness of atomic initial segments" (http://en.wikipedia.org/wiki/Completeness_of_atomic_initial_sequents) *)
- ; al_horiz_expand_left_reflexive : forall a b, [#al_reflexive_seq b#];;[#al_horiz_expand_left a#]===[#al_reflexive_seq (a,,b)#]
- ; al_horiz_expand_right_reflexive : forall a b, [#al_reflexive_seq a#];;[#al_horiz_expand_right b#]===[#al_reflexive_seq (a,,b)#]
- ; al_horiz_expand_right_then_cancel : forall a,
- ((([#al_reflexive_seq (a,, [])#] ;; [#al_ant_cancelr#]);; [#al_suc_cancelr#]) === [#al_reflexive_seq a#])
-
- ; al_vert_expand_ant_left : forall x `(pf:[a|=b]/⋯⋯/[c|=d]), [x,,a |= b ]/⋯⋯/[x,,c |= d ]
- ; al_vert_expand_ant_right : forall x `(pf:[a|=b]/⋯⋯/[c|=d]), [ a,,x|= b ]/⋯⋯/[ c,,x|= d ]
- ; al_vert_expand_suc_left : forall x `(pf:[a|=b]/⋯⋯/[c|=d]), [ a |=x,,b ]/⋯⋯/[ c |=x,,d ]
- ; al_vert_expand_suc_right : forall x `(pf:[a|=b]/⋯⋯/[c|=d]), [ a |= b,,x]/⋯⋯/[ c |= d,,x]
- ; al_vert_expand_ant_l_respects : forall x a b c d (f g:[a|=b]/⋯⋯/[c|=d]),
- f===g -> al_vert_expand_ant_left x f === al_vert_expand_ant_left x g
- ; al_vert_expand_ant_r_respects : forall x a b c d (f g:[a|=b]/⋯⋯/[c|=d]),
- f===g -> al_vert_expand_ant_right x f === al_vert_expand_ant_right x g
- ; al_vert_expand_suc_l_respects : forall x a b c d (f g:[a|=b]/⋯⋯/[c|=d]),
- f===g -> al_vert_expand_suc_left x f === al_vert_expand_suc_left x g
- ; al_vert_expand_suc_r_respects : forall x a b c d (f g:[a|=b]/⋯⋯/[c|=d]),
- f===g -> al_vert_expand_suc_right x f === al_vert_expand_suc_right x g
- ; al_vert_expand_ant_l_preserves_id : forall x a b, al_vert_expand_ant_left x (nd_id [a|=b]) === nd_id [x,,a|=b]
- ; al_vert_expand_ant_r_preserves_id : forall x a b, al_vert_expand_ant_right x (nd_id [a|=b]) === nd_id [a,,x|=b]
- ; al_vert_expand_suc_l_preserves_id : forall x a b, al_vert_expand_suc_left x (nd_id [a|=b]) === nd_id [a|=x,,b]
- ; al_vert_expand_suc_r_preserves_id : forall x a b, al_vert_expand_suc_right x (nd_id [a|=b]) === nd_id [a|=b,,x]
- ; al_vert_expand_ant_l_preserves_comp : forall x a b c d e f (h:[a|=b]/⋯⋯/[c|=d])(g:[c|=d]/⋯⋯/[e|=f]),
- (al_vert_expand_ant_left x (h;;g)) === (al_vert_expand_ant_left x h);;(al_vert_expand_ant_left x g)
- ; al_vert_expand_ant_r_preserves_comp : forall x a b c d e f (h:[a|=b]/⋯⋯/[c|=d])(g:[c|=d]/⋯⋯/[e|=f]),
- (al_vert_expand_ant_right x (h;;g)) === (al_vert_expand_ant_right x h);;(al_vert_expand_ant_right x g)
- ; al_vert_expand_suc_l_preserves_comp : forall x a b c d e f (h:[a|=b]/⋯⋯/[c|=d])(g:[c|=d]/⋯⋯/[e|=f]),
- (al_vert_expand_suc_left x (h;;g)) === (al_vert_expand_suc_left x h);;(al_vert_expand_suc_left x g)
- ; al_vert_expand_suc_r_preserves_comp : forall x a b c d e f (h:[a|=b]/⋯⋯/[c|=d])(g:[c|=d]/⋯⋯/[e|=f]),
- (al_vert_expand_suc_right x (h;;g)) === (al_vert_expand_suc_right x h);;(al_vert_expand_suc_right x g)
-
- ; al_subst : forall a b c, [ a |= b ] ,, [ b |= c ] /⋯⋯/ [ a |= c ]
- ; al_subst_associativity : forall {a b c d},
- ((al_subst a b c) ** (nd_id1 (c|=d))) ;;
- (al_subst a c d)
- ===
- nd_assoc ;;
- ((nd_id1 (a|=b)) ** (al_subst b c d) ;;
- (al_subst a b d))
- ; al_subst_associativity' : forall {a b c d},
- nd_cossa ;;
- ((al_subst a b c) ** (nd_id1 (c|=d))) ;;
- (al_subst a c d)
- ===
- ((nd_id1 (a|=b)) ** (al_subst b c d) ;;
- (al_subst a b d))
-
- ; al_subst_left_identity : forall `(pf:h/⋯⋯/[t1|=t2]), nd_llecnac;;(( [#al_reflexive_seq t1#]**pf);; al_subst _ _ _) === pf
- ; al_subst_right_identity : forall `(pf:h/⋯⋯/[t1|=t2]), nd_rlecnac;;((pf**[#al_reflexive_seq t2#] );; al_subst _ _ _) === pf
- ; al_subst_commutes_with_horiz_expand_left : forall a b c d,
- [#al_horiz_expand_left d#] ** [#al_horiz_expand_left d#];; al_subst (d,, a) (d,, b) (d,, c)
- === al_subst a b c;; [#al_horiz_expand_left d#]
- ; al_subst_commutes_with_horiz_expand_right : forall a b c d,
- [#al_horiz_expand_right d#] ** [#al_horiz_expand_right d#] ;; al_subst (a,, d) (b,, d) (c,, d)
- === al_subst a b c;; [#al_horiz_expand_right d#]
- ; al_subst_commutes_with_vertical_expansion : forall t0 t1 t2, forall (f:[[]|=t1]/⋯⋯/[[]|=t0])(g:[[]|=t0]/⋯⋯/[[]|=t2]),
- (((nd_rlecnac;;
- ((([#al_reflexive_seq (t1,, [])#];; al_vert_expand_ant_left t1 (al_vert_expand_suc_right [] f));;
- (nd_rule al_ant_cancelr));; (nd_rule al_suc_cancelr)) ** nd_id0);;
- (nd_id [t1 |= t0]) **
- ((([#al_reflexive_seq (t0,, [])#];; al_vert_expand_ant_left t0 (al_vert_expand_suc_right [] g));;
- (nd_rule al_ant_cancelr));; (nd_rule al_suc_cancelr)));;
- al_subst t1 t0 t2)
- ===
- ((([#al_reflexive_seq (t1,, [])#];;
- (al_vert_expand_ant_left t1 (al_vert_expand_suc_right [] f);;
- al_vert_expand_ant_left t1 (al_vert_expand_suc_right [] g)));;
- (nd_rule al_ant_cancelr));; (nd_rule al_suc_cancelr))
- }.
-
- Notation "pf1 === pf2" := (@ndr_eqv _ _ al_eqv _ _ pf1 pf2) : temporary_scope3.
- Open Scope temporary_scope3.
-
- Lemma al_subst_respects :
- forall {AL:AcceptableLanguage}{a b c},
- forall
- (f : [] /⋯⋯/ [a |= b])
- (f' : [] /⋯⋯/ [a |= b])
- (g : [] /⋯⋯/ [b |= c])
- (g' : [] /⋯⋯/ [b |= c]),
- (f === f') ->
- (g === g') ->
- (f ** g;; al_subst _ _ _) === (f' ** g';; al_subst _ _ _).
- intros.
- setoid_rewrite H.
- setoid_rewrite H0.
- reflexivity.
- Defined.
-
- (* a contextually closed language *)
- (*
- Class ContextuallyClosedAcceptableLanguage :=
- { ccal_al : AcceptableLanguage
- ; ccal_contextual_closure_operator : Tree ??T -> Tree ??T -> Tree ??T
- where "a -~- b" := (ccal_contextual_closure_operator a b)
- ; ccal_contextual_closure : forall {a b c d}(f:[a|=b]/⋯⋯/[c|=d]), [[]|=a-~-b]/⋯⋯/[[]|=c-~-d]
- ; ccal_contextual_closure_respects : forall {a b c d}(f f':[a|=b]/⋯⋯/[c|=d]),
- f===f' -> (ccal_contextual_closure f)===(ccal_contextual_closure f')
- ; ccal_contextual_closure_preserves_comp : forall {a b c d e f}(f':[a|=b]/⋯⋯/[c|=d])(g':[c|=d]/⋯⋯/[e|=f]),
- (ccal_contextual_closure f');;(ccal_contextual_closure g') === (ccal_contextual_closure (f';;g'))
- ; ccal_contextual_closure_preserves_id : forall {a b}, ccal_contextual_closure (nd_id [a|=b]) === nd_id [[]|=a-~-b]
- }.
- Coercion ccal_al : ContextuallyClosedAcceptableLanguage >-> AcceptableLanguage.
- *)
+ Open Scope pl_scope.
- (* languages with unrestricted substructural rules (like that of Section 5) additionally implement this class *)
- Class AcceptableLanguageWithUnrestrictedSubstructuralRules :=
- { alwusr_al :> AcceptableLanguage
- ; al_contr : forall a b, Rule [a,,a |= b ] [ a |= b]
- ; al_exch : forall a b c, Rule [a,,b |= c ] [(b,,a)|= c]
- ; al_weak : forall a b, Rule [[] |= b ] [ a |= b]
+ Class ProgrammingLanguage :=
+ { pl_eqv0 :> @ND_Relation PLJudg Rule
+ ; pl_snd :> @SequentND PLJudg Rule _ sequent
+ ; pl_cnd :> @ContextND PLJudg Rule T sequent pl_snd
+ ; pl_eqv1 :> @SequentND_Relation PLJudg Rule _ sequent pl_snd pl_eqv0
+ ; pl_eqv :> @ContextND_Relation PLJudg Rule _ sequent pl_snd pl_cnd pl_eqv0 pl_eqv1
}.
- Coercion alwusr_al : AcceptableLanguageWithUnrestrictedSubstructuralRules >-> AcceptableLanguage.
-
- (* languages with a fixpoint operator *)
- Class AcceptableLanguageWithFixpointOperator `(al:AcceptableLanguage) :=
- { alwfpo_al := al
- ; al_fix : forall a b x, Rule [a,,x |= b,,x] [a |= b]
- }.
- Coercion alwfpo_al : AcceptableLanguageWithFixpointOperator >-> AcceptableLanguage.
-
- Close Scope temporary_scope3.
- Close Scope al_scope.
- Close Scope nd_scope.
- Close Scope pf_scope.
-
-End Acceptable_Language.
-
-Implicit Arguments ND [ Judgment ].
-
-Open Scope nd_scope.
- Add Parametric Morphism {T Rule AL a b c d e} : (@al_vert_expand_suc_right T Rule AL a b c d e)
- with signature ((ndr_eqv(ND_Relation:=al_eqv)) ==> (ndr_eqv(ND_Relation:=al_eqv)))
- as parametric_morphism_al_vert_expand_suc_right.
- intros; apply al_vert_expand_suc_r_respects; auto.
- Defined.
- Add Parametric Morphism {T Rule AL a b c d e} : (@al_vert_expand_suc_left T Rule AL a b c d e)
- with signature ((ndr_eqv(ND_Relation:=al_eqv)) ==> (ndr_eqv(ND_Relation:=al_eqv)))
- as parametric_morphism_al_vert_expand_suc_left.
- intros; apply al_vert_expand_suc_l_respects; auto.
- Defined.
- Add Parametric Morphism {T Rule AL a b c d e} : (@al_vert_expand_ant_right T Rule AL a b c d e)
- with signature ((ndr_eqv(ND_Relation:=al_eqv)) ==> (ndr_eqv(ND_Relation:=al_eqv)))
- as parametric_morphism_al_vert_expand_ant_right.
- intros; apply al_vert_expand_ant_r_respects; auto.
- Defined.
- Add Parametric Morphism {T Rule AL a b c d e} : (@al_vert_expand_ant_left T Rule AL a b c d e)
- with signature ((ndr_eqv(ND_Relation:=al_eqv)) ==> (ndr_eqv(ND_Relation:=al_eqv)))
- as parametric_morphism_al_vert_expand_ant_left.
- intros; apply al_vert_expand_ant_l_respects; auto.
- Defined.
-Close Scope nd_scope.
-
-Notation "cs |= ss" := (@sequent _ cs ss) : al_scope.
-(*
-Definition mapSequent {T R:Type}(f:Tree ??T -> Tree ??R)(seq:@Sequent T) : @Sequent R :=
- match seq with sequentpair a b => pair (f a) (f b) end.
-Implicit Arguments Sequent [ ].
-*)
-
-
-(* proofs which are generic and apply to any acceptable langauge (most of section 4) *)
-Section Acceptable_Language_Facts.
-
- (* the ambient language about which we are proving facts *)
- Context `(Lang : @AcceptableLanguage T Rule).
-
- (* just for this section *)
- Open Scope nd_scope.
- Open Scope al_scope.
- Open Scope pf_scope.
- Notation "H /⋯⋯/ C" := (@ND Sequent Rule H C) : temporary_scope4.
- Notation "a === b" := (@ndr_eqv _ _ al_eqv _ _ a b) : temporary_scope4.
- Open Scope temporary_scope4.
-
- Definition lang_al_eqv := al_eqv(AcceptableLanguage:=Lang).
- Existing Instance lang_al_eqv.
-
- Ltac distribute :=
- match goal with
- [ |- ?G ] =>
- match G with
- context ct [(?A ** ?B) ;; (?C ** ?D)] =>
- setoid_rewrite <- (ndr_prod_preserves_comp A B C D)
- end
- end.
-
- Ltac sequentialize_product A B :=
- match goal with
- [ |- ?G ] =>
- match G with
- | context ct [(A ** B)] =>
- setoid_replace (A ** B)
- with ((A ** (nd_id _)) ;; ((nd_id _) ** B))
- (*with ((A ** (nd_id _)) ;; ((nd_id _) ** B))*)
- end end.
- Ltac sequentialize_product' A B :=
- match goal with
- [ |- ?G ] =>
- match G with
- | context ct [(A ** B)] =>
- setoid_replace (A ** B)
- with (((nd_id _) ** B) ;; (A ** (nd_id _)))
- (*with ((A ** (nd_id _)) ;; ((nd_id _) ** B))*)
- end end.
- Ltac distribute' :=
- match goal with
- [ |- ?G ] =>
- match G with
- context ct [(?A ;; ?B) ** (?C ;; ?D)] =>
- setoid_rewrite (ndr_prod_preserves_comp A B C D)
- end
- end.
- Ltac distribute_left_product_with_id :=
- match goal with
- [ |- ?G ] =>
- match G with
- context ct [(nd_id ?A) ** (?C ;; ?D)] =>
- setoid_replace ((nd_id A) ** (C ;; D)) with ((nd_id A ;; nd_id A) ** (C ;; D));
- [ setoid_rewrite (ndr_prod_preserves_comp (nd_id A) C (nd_id A) D) | idtac ]
- end
- end.
- Ltac distribute_right_product_with_id :=
- match goal with
- [ |- ?G ] =>
- match G with
- context ct [(?C ;; ?D) ** (nd_id ?A)] =>
- setoid_replace ((C ;; D) ** (nd_id A)) with ((C ;; D) ** (nd_id A ;; nd_id A));
- [ setoid_rewrite (ndr_prod_preserves_comp C (nd_id A) D (nd_id A)) | idtac ]
- end
- end.
-
- (* another phrasing of al_subst_associativity; obligations tend to show up in this form *)
- Lemma al_subst_associativity'' :
- forall (a b : T) (f : [] /⋯⋯/ [[a] |= [b]]) (c : T) (g : [] /⋯⋯/ [[b] |= [c]])
- (d : T) (h : [] /⋯⋯/ [[c] |= [d]]),
- nd_llecnac;; ((nd_llecnac;; (f ** g;; al_subst [a] [b] [c])) ** h;; al_subst [a] [c] [d]) ===
- nd_llecnac;; (f ** (nd_llecnac;; (g ** h;; al_subst [b] [c] [d]));; al_subst [a] [b] [d]).
- intros.
- sequentialize_product' (nd_llecnac;; (f ** g;; al_subst [a] [b] [c])) h.
- repeat setoid_rewrite <- ndr_comp_associativity.
- distribute_right_product_with_id.
- repeat setoid_rewrite ndr_comp_associativity.
- set (@al_subst_associativity) as q. setoid_rewrite q. clear q.
- apply ndr_comp_respects; try reflexivity.
- repeat setoid_rewrite <- ndr_comp_associativity.
- apply ndr_comp_respects; try reflexivity.
- sequentialize_product f ((nd_llecnac;; g ** h);; al_subst [b] [c] [d]).
- distribute_left_product_with_id.
- repeat setoid_rewrite <- ndr_comp_associativity.
- apply ndr_comp_respects; try reflexivity.
- setoid_rewrite <- ndr_prod_preserves_comp.
- repeat setoid_rewrite ndr_comp_left_identity.
- repeat setoid_rewrite ndr_comp_right_identity.
- admit.
- admit.
- admit.
- admit.
- admit.
- Qed.
-
- (* Formalized Definition 4.6 *)
- Section Types1.
- Instance Types1 : Category T (fun t1 t2 => [ ] /⋯⋯/ [ [t1] |= [t2] ]) :=
- { eqv := fun ta tb pf1 pf2 => pf1 === pf2
- ; id := fun t => [#al_reflexive_seq [t]#]
- ; comp := fun {ta tb tc:T}(pf1:[]/⋯⋯/[[ta]|=[tb]])(pf2:[]/⋯⋯/[[tb]|=[tc]]) => nd_llecnac ;; ((pf1 ** pf2) ;; (al_subst _ _ _))
- }.
- intros; apply Build_Equivalence;
- [ unfold Reflexive; intros; reflexivity
- | unfold Symmetric; intros; symmetry; auto
- | unfold Transitive; intros; transitivity y; auto ].
- unfold Proper; unfold respectful; intros; simpl.
- apply ndr_comp_respects. reflexivity.
- apply al_subst_respects; auto.
- intros; simpl. apply al_subst_left_identity.
- intros; simpl.
- assert (@nd_llecnac _ Rule [] === @nd_rlecnac _ _ []).
- apply ndr_structural_indistinguishable; auto.
- setoid_rewrite H.
- apply al_subst_right_identity.
- intros; apply al_subst_associativity''.
- Defined.
- End Types1.
-
- (* Formalized Definition 4.10 *)
- Instance Judgments : Category (Tree ??Sequent) (fun h c => h /⋯⋯/ c) :=
- { id := fun h => nd_id _
- ; comp := fun a b c f g => f ;; g
- ; eqv := fun a b f g => f===g
- }.
- intros; apply Build_Equivalence;
- [ unfold Reflexive; intros; reflexivity
- | unfold Symmetric; intros; symmetry; auto
- | unfold Transitive; intros; transitivity y; auto ].
- unfold Proper; unfold respectful; intros; simpl; apply ndr_comp_respects; auto.
- intros; apply ndr_comp_left_identity.
- intros; apply ndr_comp_right_identity.
- intros; apply ndr_comp_associativity.
- Defined.
-
- (* a "primitive" proof has exactly one hypothesis and one conclusion *)
- Inductive IsPrimitive : forall (h_:Tree ??(@Sequent T)), Type :=
- isPrimitive : forall h, IsPrimitive [h].
- Hint Constructors IsPrimitive.
- Instance IsPrimitiveSubCategory : SubCategory Judgments IsPrimitive (fun _ _ _ _ _ => True).
- apply Build_SubCategory; intros; auto.
- Defined.
-
- (* The primitive judgments form a subcategory; nearly all of the
- * functors we build that go into Judgments will factor through the
- * inclusion functor for this subcategory. Explicitly constructing
- * it makes the formalization easier, but distracts from what's
- * actually going on (from an expository perspective) *)
- Definition PrimitiveJudgments := SubCategoriesAreCategories Judgments IsPrimitiveSubCategory.
- Definition PrimitiveInclusion := InclusionFunctor Judgments IsPrimitiveSubCategory.
-
- Section Types0.
- Inductive IsNil : Tree ??(@Sequent T) -> Prop := isnil : IsNil [].
- Inductive IsClosed : Tree ??(@Sequent T) -> Prop := isclosed:forall t, IsClosed [[]|=[t]].
- Inductive IsIdentity : forall h c, (h /⋯⋯/ c) -> Prop :=
- | isidentity0 : forall t, IsIdentity t t (nd_id t)
- | isidentity1 : forall t pf1 pf2, IsIdentity t t pf1 -> IsIdentity t t pf2 -> IsIdentity t t (pf1 ;; pf2).
- Inductive IsInTypes0 (h c:Tree ??Sequent)(pf:h /⋯⋯/ c) : Prop :=
- | iit0_id0 : IsNil h -> IsNil c -> IsIdentity _ _ pf -> IsInTypes0 _ _ pf
- | iit0_id1 : @IsClosed h -> @IsClosed c -> IsIdentity _ _ pf -> IsInTypes0 _ _ pf
- | iit0_term : IsNil h -> @IsClosed c -> IsInTypes0 _ _ pf.
- Instance Types0P : SubCategory Judgments
- (fun x:Judgments => IsInTypes0 _ _ (id(Category:=Judgments) x))
- (fun h c _ _ f => IsInTypes0 h c f).
- intros.
- apply Build_SubCategory; intros; simpl.
- auto.
- inversion H0.
- inversion H1; subst.
- inversion H2; subst.
- inversion H; subst. inversion H4; subst.
- apply iit0_id0; auto. apply isidentity1; auto.
- inversion H5.
- inversion H5.
- inversion H1; subst.
- inversion H2; subst.
- inversion H3; subst. clear H8. clear H7.
- inversion H; subst. inversion H5.
- inversion H4; subst.
- inversion H6; subst.
- apply iit0_id1; auto. apply isidentity1; auto.
- clear H10. clear H8.
- apply iit0_id1; auto. apply isidentity1; auto.
- inversion H4; subst. inversion H; subst.
- inversion H8.
- inversion H6.
- apply iit0_term; auto.
- clear H7; subst.
- inversion H; subst.
- inversion H4; subst.
- apply iit0_term; auto.
- inversion H4; subst.
- inversion H7; subst. clear H14.
- apply iit0_id1; auto. apply isidentity1; auto.
- clear H13.
- apply iit0_id1; auto. apply isidentity1; auto.
- inversion H4; subst.
- inversion H; subst.
- inversion H10.
- inversion H7.
- apply iit0_term; auto.
- inversion H1; subst.
- inversion H; subst.
- inversion H3; subst. apply iit0_term; auto.
- inversion H4.
- inversion H4.
- Qed.
-
- (* Formalized Definition 4.8 *)
- Definition Types0 := SubCategoriesAreCategories Judgments Types0P.
- End Types0.
-
- (* Formalized Definition 4.11 *)
- Instance Judgments_binoidal : BinoidalCat Judgments (fun a b:Tree ??Sequent => a,,b) :=
- { bin_first := fun x => @Build_Functor _ _ Judgments _ _ Judgments (fun a => a,,x) (fun a b (f:a/⋯⋯/b) => f**(nd_id x)) _ _ _
- ; bin_second := fun x => @Build_Functor _ _ Judgments _ _ Judgments (fun a => x,,a) (fun a b (f:a/⋯⋯/b) => (nd_id x)**f) _ _ _
- }.
- intros. simpl. simpl in H. setoid_rewrite H. reflexivity.
- intros. simpl. reflexivity.
- intros. simpl. setoid_rewrite <- ndr_prod_preserves_comp. setoid_rewrite ndr_comp_left_identity. reflexivity.
- intros. simpl. simpl in H. setoid_rewrite H. reflexivity.
- intros. simpl. reflexivity.
- intros. simpl. setoid_rewrite <- ndr_prod_preserves_comp. setoid_rewrite ndr_comp_left_identity. reflexivity.
- Defined.
-
- Definition jud_assoc_iso (a b c:Judgments) : @Isomorphic _ _ Judgments ((a,,b),,c) (a,,(b,,c)).
- apply (@Build_Isomorphic _ _ Judgments _ _ nd_assoc nd_cossa); simpl; auto.
- Defined.
- Definition jud_cancelr_iso (a:Judgments) : @Isomorphic _ _ Judgments (a,,[]) a.
- apply (@Build_Isomorphic _ _ Judgments _ _ nd_cancelr nd_rlecnac); simpl; auto.
- Defined.
- Definition jud_cancell_iso (a:Judgments) : @Isomorphic _ _ Judgments ([],,a) a.
- apply (@Build_Isomorphic _ _ Judgments _ _ nd_cancell nd_llecnac); simpl; auto.
- Defined.
-
- (* just for this section *)
- Notation "a ⊗ b" := (@bin_obj _ _ Judgments _ Judgments_binoidal a b).
- Notation "c ⋊ -" := (@bin_second _ _ Judgments _ Judgments_binoidal c).
- Notation "- ⋉ c" := (@bin_first _ _ Judgments _ Judgments_binoidal c).
- Notation "c ⋊ f" := ((c ⋊ -) \ f).
- Notation "g ⋉ c" := ((- ⋉ c) \ g).
-
- Hint Extern 1 => apply (@nd_structural_id0 _ Rule).
- Hint Extern 1 => apply (@nd_structural_id1 _ Rule).
- Hint Extern 1 => apply (@nd_structural_weak _ Rule).
- Hint Extern 1 => apply (@nd_structural_copy _ Rule).
- Hint Extern 1 => apply (@nd_structural_prod _ Rule).
- Hint Extern 1 => apply (@nd_structural_comp _ Rule).
- Hint Extern 1 => apply (@nd_structural_cancell _ Rule).
- Hint Extern 1 => apply (@nd_structural_cancelr _ Rule).
- Hint Extern 1 => apply (@nd_structural_llecnac _ Rule).
- Hint Extern 1 => apply (@nd_structural_rlecnac _ Rule).
- Hint Extern 1 => apply (@nd_structural_assoc _ Rule).
- Hint Extern 1 => apply (@nd_structural_cossa _ Rule).
- Hint Extern 2 => apply (@ndr_structural_indistinguishable _ Rule).
-
- Program Instance Judgments_premonoidal : PreMonoidalCat Judgments_binoidal [ ] :=
- { pmon_assoc := fun a b => @Build_NaturalIsomorphism _ _ _ _ _ _ _ _ _ _ (fun x => (jud_assoc_iso a x b)) _
- ; pmon_cancell := @Build_NaturalIsomorphism _ _ _ _ _ _ _ _ _ _ (fun x => (jud_cancell_iso x)) _
- ; pmon_cancelr := @Build_NaturalIsomorphism _ _ _ _ _ _ _ _ _ _ (fun x => (jud_cancelr_iso x)) _
- ; pmon_assoc_rr := fun a b => @Build_NaturalIsomorphism _ _ _ _ _ _ _ _ _ _ (fun x => (jud_assoc_iso x a b)⁻¹) _
- ; pmon_assoc_ll := fun a b => @Build_NaturalIsomorphism _ _ _ _ _ _ _ _ _ _ (fun x => jud_assoc_iso a b x) _
- }.
- Next Obligation.
- setoid_rewrite (ndr_prod_associativity (nd_id a) f (nd_id b)).
- repeat setoid_rewrite ndr_comp_associativity.
- apply ndr_comp_respects; try reflexivity.
- symmetry.
- eapply transitivity; [ idtac | apply ndr_comp_right_identity ].
- apply ndr_comp_respects; try reflexivity; simpl; auto.
- Defined.
- Next Obligation.
- setoid_rewrite (ndr_prod_right_identity f).
- repeat setoid_rewrite ndr_comp_associativity.
- apply ndr_comp_respects; try reflexivity.
- symmetry.
- eapply transitivity; [ idtac | apply ndr_comp_right_identity ].
- apply ndr_comp_respects; try reflexivity; simpl; auto.
- Defined.
- Next Obligation.
- setoid_rewrite (ndr_prod_left_identity f).
- repeat setoid_rewrite ndr_comp_associativity.
- apply ndr_comp_respects; try reflexivity.
- symmetry.
- eapply transitivity; [ idtac | apply ndr_comp_right_identity ].
- apply ndr_comp_respects; try reflexivity; simpl; auto.
- Defined.
- Next Obligation.
- apply Build_Pentagon; intros.
- simpl; apply ndr_structural_indistinguishable; auto.
- Defined.
- Next Obligation.
- apply Build_Triangle; intros;
- simpl; apply ndr_structural_indistinguishable; auto.
- Defined.
- Next Obligation.
- setoid_rewrite (ndr_prod_associativity f (nd_id a) (nd_id b)).
- repeat setoid_rewrite <- ndr_comp_associativity.
- apply ndr_comp_respects; try reflexivity.
- eapply transitivity; [ idtac | apply ndr_comp_left_identity ].
- apply ndr_comp_respects; try reflexivity; simpl; auto.
- Defined.
- Next Obligation.
- setoid_rewrite (ndr_prod_associativity (nd_id a) (nd_id b) f).
- repeat setoid_rewrite ndr_comp_associativity.
- apply ndr_comp_respects; try reflexivity.
- symmetry.
- eapply transitivity; [ idtac | apply ndr_comp_right_identity ].
- apply ndr_comp_respects; try reflexivity; simpl; auto.
- Defined.
- Check (@Judgments_premonoidal). (* to force Coq to verify that we've finished all the obligations *)
-
- Definition Judgments_monoidal_endofunctor_fobj : Judgments ×× Judgments -> Judgments :=
- (fun xy =>
- match xy with
- | pair_obj x y => T_Branch x y
- end).
- Definition Judgments_monoidal_endofunctor_fmor :
- forall a b, (a~~{Judgments ×× Judgments}~~>b) ->
- ((Judgments_monoidal_endofunctor_fobj a)~~{Judgments}~~>(Judgments_monoidal_endofunctor_fobj b)).
- intros.
- destruct a.
- destruct b.
- destruct X.
- exact (h**h0).
- Defined.
- Definition Judgments_monoidal_endofunctor : Functor (Judgments ×× Judgments) Judgments Judgments_monoidal_endofunctor_fobj.
- refine {| fmor := Judgments_monoidal_endofunctor_fmor |}; intros; simpl.
- abstract (destruct a; destruct b; destruct f; destruct f'; auto; destruct H; apply ndr_prod_respects; auto).
- abstract (destruct a; simpl; reflexivity).
- abstract (destruct a; destruct b; destruct c; destruct f; destruct g; symmetry; apply ndr_prod_preserves_comp).
- Defined.
-
- Instance Judgments_monoidal : MonoidalCat _ _ Judgments_monoidal_endofunctor [ ].
- admit.
- Defined.
-
- (* all morphisms in the category of Judgments are central; there's probably a very short route from here to CartesianCat *)
- Lemma all_central : forall a b:Judgments, forall (f:a~>b), CentralMorphism f.
- intros; apply Build_CentralMorphism; intros.
- simpl.
- setoid_rewrite <- (ndr_prod_preserves_comp f (nd_id _) (nd_id _) g).
- setoid_rewrite <- (ndr_prod_preserves_comp (nd_id _) g f (nd_id _)).
- setoid_rewrite ndr_comp_left_identity.
- setoid_rewrite ndr_comp_right_identity.
- reflexivity.
- simpl.
- setoid_rewrite <- (ndr_prod_preserves_comp g (nd_id _) (nd_id _) f).
- setoid_rewrite <- (ndr_prod_preserves_comp (nd_id _) f g (nd_id _)).
- setoid_rewrite ndr_comp_left_identity.
- setoid_rewrite ndr_comp_right_identity.
- reflexivity.
- Defined.
-
- (*
- Instance NoHigherOrderFunctionTypes : SubCategory Judgments
- Instance NoFunctionTypes : SubCategory Judgments
- Lemma first_order_functions_eliminable : IsomorphicCategories NoHigherOrderFunctionTypes NoFunctionTypes
- *)
-
- (* Formalized Theorem 4.19 *)
- Instance Types_omega_e : ECategory Judgments_monoidal (Tree ??T) (fun tt1 tt2 => [ tt1 |= tt2 ]) :=
- { eid := fun tt => [#al_reflexive_seq tt#]
- ; ecomp := fun a b c => al_subst a b c
- }.
- admit.
- admit.
- admit.
- admit.
- admit.
- Defined.
-
- Definition Types_omega_monoidal_functor
- : Functor (Types_omega_e ×× Types_omega_e) Types_omega_e (fun a => match a with pair_obj a1 a2 => a1,,a2 end).
- admit.
- Defined.
-
- Instance Types_omega_monoidal : MonoidalCat Types_omega_e _ Types_omega_monoidal_functor [].
- admit.
- Defined.
-
- Definition AL_Enrichment : Enrichment.
- refine {| enr_c := Types_omega_e |}.
- Defined.
-
- Definition AL_SurjectiveEnrichment : SurjectiveEnrichment.
- refine {| se_enr := AL_Enrichment |}.
- unfold treeDecomposition.
- intros; induction d; simpl.
- destruct a.
- destruct s.
- exists [pair t t0]; auto.
- exists []; auto.
- destruct IHd1.
- destruct IHd2.
- exists (x,,x0); subst; auto.
- Defined.
-
- Definition AL_MonoidalEnrichment : MonoidalEnrichment.
- refine {| me_enr := AL_SurjectiveEnrichment ; me_mon := Types_omega_monoidal |}.
- admit.
- Defined.
-
- Definition AL_MonicMonoidalEnrichment : MonicMonoidalEnrichment.
- refine {| ffme_enr := AL_MonoidalEnrichment |}.
- admit.
- admit.
- admit.
- Defined.
-
- (*
- Instance Types_omega_be : BinoidalECategory Types_omega_e :=
- { bec_obj := fun tt1 tt2 => tt1,,tt2
- ; bec_efirst := fun a b c => nd_rule (@al_horiz_expand_right _ _ Lang _ _ _)
- ; bec_esecond := fun a b c => nd_rule (@al_horiz_expand_left _ _ Lang _ _ _)
- }.
- intros; apply all_central.
- intros; apply all_central.
- intros. unfold eid. simpl.
- setoid_rewrite <- al_horiz_expand_right_reflexive.
- reflexivity.
- intros. unfold eid. simpl.
- setoid_rewrite <- al_horiz_expand_left_reflexive.
- reflexivity.
- intros. simpl.
- set (@al_subst_commutes_with_horiz_expand_right _ _ _ a b c d) as q.
- setoid_rewrite <- q. clear q.
- apply ndr_comp_respects; try reflexivity.
- distribute.
- apply ndr_prod_respects.
- eapply transitivity; [ idtac | apply ndr_comp_right_identity ].
- apply ndr_comp_respects; reflexivity.
- eapply transitivity; [ idtac | apply ndr_comp_left_identity ].
- apply ndr_comp_respects; reflexivity.
- intros. simpl.
- set (@al_subst_commutes_with_horiz_expand_left _ _ _ a b c d) as q.
- setoid_rewrite <- q. clear q.
- apply ndr_comp_respects; try reflexivity.
- distribute.
- apply ndr_prod_respects.
- eapply transitivity; [ idtac | apply ndr_comp_right_identity ].
- apply ndr_comp_respects; reflexivity.
- eapply transitivity; [ idtac | apply ndr_comp_left_identity ].
- apply ndr_comp_respects; reflexivity.
- Defined.
- *)
-
- Definition Types_omega : Category _ (fun tt1 tt2 => [ ]/⋯⋯/[ tt1 |= tt2 ]) := Underlying Types_omega_e.
- Existing Instance Types_omega.
-
- (*
- Definition Types_omega_binoidal : BinoidalCat Types_omega (fun tt1 tt2 => tt1,,tt2) := Underlying_binoidal Types_omega_be.
- Existing Instance Types_omega_binoidal.
- *)
-
- (* takes an "operation in the context" (proof from [b|=Top]/⋯⋯/[a|=Top]) and turns it into a function a-->b; note the variance *)
- Definition context_operation_as_function
- : forall {a}{b} (f:[b|=[]]~~{Judgments}~~>[a|=[]]), []~~{Judgments}~~>[a|=b].
- intros.
- apply (@al_vert_expand_suc_right _ _ _ b _ _) in f.
- simpl in f.
- apply (@al_vert_expand_ant_left _ _ _ [] _ _) in f.
- simpl in f.
- set ([#al_reflexive_seq _#] ;; f ;; [#al_ant_cancell#] ;; [#al_suc_cancell#]) as f'.
- exact f'.
- Defined.
-
- (* takes an "operation in the context" (proof from [Top|=a]/⋯⋯/[Top|=b]) and turns it into a function a-->b; note the variance *)
- Definition cocontext_operation_as_function
- : forall {a}{b} (f:[[]|=a]~~{Judgments}~~>[[]|=b]), []~~{Judgments}~~>[a|=b].
- intros. unfold hom. unfold hom in f.
- apply al_vert_expand_ant_right with (x:=a) in f.
- simpl in f.
- apply al_vert_expand_suc_left with (x:=[]) in f.
- simpl in f.
- set ([#al_reflexive_seq _#] ;; f ;; [#al_ant_cancell#] ;; [#al_suc_cancell#]) as f'.
- exact f'.
- Defined.
-
-
- Definition function_as_context_operation
- : forall {a}{b}{c} (f:[]~~{Judgments}~~>[a|=b]), [b|=c]~~{Judgments}~~>[a|=c]
- := fun a b c f => RepresentableFunctorºᑭ Types_omega_e c \ f.
- Definition function_as_cocontext_operation
- : forall {a}{b}{c} (f:[]/⋯⋯/[a|=b]), [c|=a]~~{Judgments}~~>[c|=b]
- := fun a b c f => RepresentableFunctor Types_omega_e c \ f.
+ Notation "pf1 === pf2" := (@ndr_eqv _ _ pl_eqv _ _ pf1 pf2) : temporary_scope3.
+ Coercion pl_eqv : ProgrammingLanguage >-> ContextND_Relation.
+ Coercion pl_cnd : ProgrammingLanguage >-> ContextND.
- Close Scope temporary_scope4.
- Close Scope al_scope.
- Close Scope nd_scope.
- Close Scope pf_scope.
- Close Scope isomorphism_scope.
-End Acceptable_Language_Facts.
+End Programming_Language.
-Coercion AL_SurjectiveEnrichment : AcceptableLanguage >-> SurjectiveEnrichment.
-Coercion AL_MonicMonoidalEnrichment : AcceptableLanguage >-> MonicMonoidalEnrichment.