Add semwt and its renaming lemmas

This commit is contained in:
Yiyun Liu 2024-12-30 21:43:41 -05:00
parent 1a9cd6bda9
commit 5347d573b5

View file

@ -5,18 +5,19 @@ From Equations Require Import Equations.
Require Import ssreflect ssrbool.
Require Import Logic.PropExtensionality (propositional_extensionality).
From stdpp Require Import relations (rtc(..), rtc_subrel).
Definition ProdSpace {n} (PA : Tm n -> Prop)
(PF : Tm n -> (Tm n -> Prop) -> Prop) b : Prop :=
Import Psatz.
Definition ProdSpace (PA : Tm 0 -> Prop)
(PF : Tm 0 -> (Tm 0 -> Prop) -> Prop) b : Prop :=
forall a PB, PA a -> PF a PB -> PB (App b a).
Definition SumSpace {n} (PA : Tm n -> Prop)
(PF : Tm n -> (Tm n -> Prop) -> Prop) t : Prop :=
Definition SumSpace (PA : Tm 0 -> Prop)
(PF : Tm 0 -> (Tm 0 -> Prop) -> Prop) t : Prop :=
exists a b, rtc RPar.R t (Pair a b) /\ PA a /\ (forall PB, PF a PB -> PB b).
Definition BindSpace {n} p := if p is TPi then @ProdSpace n else @SumSpace n.
Definition BindSpace p := if p is TPi then ProdSpace else SumSpace.
Reserved Notation "⟦ A ⟧ i ;; I ↘ S" (at level 70).
Inductive InterpExt {n} i (I : forall n, nat -> Tm n -> Prop) : Tm n -> (Tm n -> Prop) -> Prop :=
Inductive InterpExt i (I : nat -> Tm 0 -> Prop) : Tm 0 -> (Tm 0 -> Prop) -> Prop :=
| InterpExt_Bind p A B PA PF :
A i ;; I PA ->
(forall a, PA a -> exists PB, PF a PB) ->
@ -25,7 +26,7 @@ Inductive InterpExt {n} i (I : forall n, nat -> Tm n -> Prop) : Tm n -> (Tm n ->
| InterpExt_Univ j :
j < i ->
Univ j i ;; I (I n j)
Univ j i ;; I (I j)
| InterpExt_Step A A0 PA :
RPar.R A A0 ->
@ -33,25 +34,25 @@ Inductive InterpExt {n} i (I : forall n, nat -> Tm n -> Prop) : Tm n -> (Tm n ->
A i ;; I PA
where "⟦ A ⟧ i ;; I ↘ S" := (InterpExt i I A S).
Lemma InterpExt_Univ' {n} i I j (PF : Tm n -> Prop) :
PF = I n j ->
Lemma InterpExt_Univ' i I j (PF : Tm 0 -> Prop) :
PF = I j ->
j < i ->
Univ j i ;; I PF.
Proof. hauto lq:on ctrs:InterpExt. Qed.
Infix "<?" := Compare_dec.lt_dec (at level 60).
Equations InterpUnivN n (i : nat) : Tm n -> (Tm n -> Prop) -> Prop by wf i lt :=
InterpUnivN n i := @InterpExt n i
(fun n j A =>
Equations InterpUnivN (i : nat) : Tm 0 -> (Tm 0 -> Prop) -> Prop by wf i lt :=
InterpUnivN i := @InterpExt i
(fun j A =>
match j <? i with
| left _ => exists PA, InterpUnivN n j A PA
| left _ => exists PA, InterpUnivN j A PA
| right _ => False
end).
Arguments InterpUnivN {n}.
Arguments InterpUnivN .
Lemma InterpExt_lt_impl {n : nat} i I I' A (PA : Tm n -> Prop) :
(forall j, j < i -> I n j = I' n j) ->
Lemma InterpExt_lt_impl i I I' A (PA : Tm 0 -> Prop) :
(forall j, j < i -> I j = I' j) ->
A i ;; I PA ->
A i ;; I' PA.
Proof.
@ -62,20 +63,20 @@ Proof.
- hauto lq:on ctrs:InterpExt.
Qed.
Lemma InterpExt_lt_eq {n : nat} i I I' A (PA : Tm n -> Prop) :
(forall j, j < i -> I n j = I' n j) ->
Lemma InterpExt_lt_eq i I I' A (PA : Tm 0 -> Prop) :
(forall j, j < i -> I j = I' j) ->
A i ;; I PA =
A i ;; I' PA.
Proof.
move => hI. apply propositional_extensionality.
have : forall j, j < i -> I' n j = I n j by sfirstorder.
have : forall j, j < i -> I' j = I j by sfirstorder.
firstorder using InterpExt_lt_impl.
Qed.
Notation "⟦ A ⟧ i ↘ S" := (InterpUnivN i A S) (at level 70).
Lemma InterpUnivN_nolt n i :
@InterpUnivN n i = @InterpExt n i (fun n j (A : Tm n) => exists PA, A j PA).
Lemma InterpUnivN_nolt i :
InterpUnivN i = InterpExt i (fun j (A : Tm 0) => exists PA, A j PA).
Proof.
simp InterpUnivN.
extensionality A. extensionality PA.
@ -91,9 +92,9 @@ Lemma RPar_substone n (a b : Tm (S n)) (c : Tm n):
RPar.R a b -> RPar.R (subst_Tm (scons c VarTm) a) (subst_Tm (scons c VarTm) b).
Proof. hauto l:on inv:option use:RPar.substing, RPar.refl. Qed.
Lemma InterpExt_Bind_inv n p i I (A : Tm n) B P
Lemma InterpExt_Bind_inv p i I (A : Tm 0) B P
(h : TBind p A B i ;; I P) :
exists (PA : Tm n -> Prop) (PF : Tm n -> (Tm n -> Prop) -> Prop),
exists (PA : Tm 0 -> Prop) (PF : Tm 0 -> (Tm 0 -> Prop) -> Prop),
A i ;; I PA /\
(forall a, PA a -> exists PB, PF a PB) /\
(forall a PB, PF a PB -> subst_Tm (scons a VarTm) B i ;; I PB) /\
@ -108,18 +109,18 @@ Proof.
hauto lq:on ctrs:InterpExt use:RPar_substone.
Qed.
Lemma InterpExt_Univ_inv n i I j P
(h : @Univ n j i ;; I P) :
P = I n j /\ j < i.
Lemma InterpExt_Univ_inv i I j P
(h : Univ j i ;; I P) :
P = I j /\ j < i.
Proof.
move : h.
move E : (@Univ n j) => T h. move : j E.
move E : (Univ j) => T h. move : j E.
elim : T P /h => //.
- hauto l:on.
- hauto lq:on rew:off inv:RPar.R.
Qed.
Lemma InterpExt_Bind_nopf n p i I (A : Tm n) B PA :
Lemma InterpExt_Bind_nopf p i I (A : Tm 0) B PA :
A i ;; I PA ->
(forall a, PA a -> exists PB, subst_Tm (scons a VarTm) B i ;; I PB) ->
TBind p A B i ;; I (BindSpace p PA (fun a PB => subst_Tm (scons a VarTm) B i ;; I PB)).
@ -127,7 +128,7 @@ Proof.
move => h0 h1. apply InterpExt_Bind =>//.
Qed.
Lemma InterpUnivN_Fun_nopf n p i (A : Tm n) B PA :
Lemma InterpUnivN_Fun_nopf p i (A : Tm 0) B PA :
A i PA ->
(forall a, PA a -> exists PB, subst_Tm (scons a VarTm) B i PB) ->
TBind p A B i (BindSpace p PA (fun a PB => subst_Tm (scons a VarTm) B i PB)).
@ -135,7 +136,7 @@ Proof.
hauto l:on use:InterpExt_Bind_nopf rew:db:InterpUniv.
Qed.
Lemma InterpExt_cumulative n i j I (A : Tm n) PA :
Lemma InterpExt_cumulative i j I (A : Tm 0) PA :
i < j ->
A i ;; I PA ->
A j ;; I PA.
@ -145,14 +146,14 @@ Proof.
hauto l:on ctrs:InterpExt use:PeanoNat.Nat.lt_trans.
Qed.
Lemma InterpUnivN_cumulative n i (A : Tm n) PA :
Lemma InterpUnivN_cumulative i (A : Tm 0) PA :
A i PA -> forall j, i < j ->
A j PA.
Proof.
hauto l:on rew:db:InterpUniv use:InterpExt_cumulative.
Qed.
Lemma InterpExt_preservation n i I (A : Tm n) B P (h : InterpExt i I A P) :
Lemma InterpExt_preservation i I (A : Tm 0) B P (h : InterpExt i I A P) :
RPar.R A B ->
B i ;; I P.
Proof.
@ -170,32 +171,32 @@ Proof.
hauto lq:on ctrs:InterpExt.
Qed.
Lemma InterpUnivN_preservation n i (A : Tm n) B P (h : A i P) :
Lemma InterpUnivN_preservation i (A : Tm 0) B P (h : A i P) :
RPar.R A B ->
B i P.
Proof. hauto l:on rew:db:InterpUnivN use: InterpExt_preservation. Qed.
Lemma InterpExt_back_preservation_star n i I (A : Tm n) B P (h : B i ;; I P) :
Lemma InterpExt_back_preservation_star i I (A : Tm 0) B P (h : B i ;; I P) :
rtc RPar.R A B ->
A i ;; I P.
Proof. induction 1; hauto l:on ctrs:InterpExt. Qed.
Lemma InterpExt_preservation_star n i I (A : Tm n) B P (h : A i ;; I P) :
Lemma InterpExt_preservation_star i I (A : Tm 0) B P (h : A i ;; I P) :
rtc RPar.R A B ->
B i ;; I P.
Proof. induction 1; hauto l:on use:InterpExt_preservation. Qed.
Lemma InterpUnivN_preservation_star n i (A : Tm n) B P (h : A i P) :
Lemma InterpUnivN_preservation_star i (A : Tm 0) B P (h : A i P) :
rtc RPar.R A B ->
B i P.
Proof. hauto l:on rew:db:InterpUnivN use:InterpExt_preservation_star. Qed.
Lemma InterpUnivN_back_preservation_star n i (A : Tm n) B P (h : B i P) :
Lemma InterpUnivN_back_preservation_star i (A : Tm 0) B P (h : B i P) :
rtc RPar.R A B ->
A i P.
Proof. hauto l:on rew:db:InterpUnivN use:InterpExt_back_preservation_star. Qed.
Lemma InterpExtInv n i I (A : Tm n) PA :
Lemma InterpExtInv i I (A : Tm 0) PA :
A i ;; I PA ->
exists B, hfb B /\ rtc RPar.R A B /\ B i ;; I PA.
Proof.
@ -209,17 +210,17 @@ Proof.
- hauto lq:on ctrs:rtc.
Qed.
Lemma RPars_Pars {n} (A B : Tm n) :
Lemma RPars_Pars (A B : Tm 0) :
rtc RPar.R A B ->
rtc Par.R A B.
Proof. hauto lq:on use:RPar_Par, rtc_subrel. Qed.
Lemma RPars_join {n} (A B : Tm n) :
Lemma RPars_join (A B : Tm 0) :
rtc RPar.R A B -> join A B.
Proof. hauto lq:on ctrs:rtc use:RPars_Pars. Qed.
Lemma bindspace_iff {n} p (PA : Tm n -> Prop) PF PF0 b :
(forall (a : Tm n) (PB PB0 : Tm n -> Prop), PF a PB -> PF0 a PB0 -> PB = PB0) ->
Lemma bindspace_iff p (PA : Tm 0 -> Prop) PF PF0 b :
(forall (a : Tm 0) (PB PB0 : Tm 0 -> Prop), PF a PB -> PF0 a PB0 -> PB = PB0) ->
(forall a, PA a -> exists PB, PF a PB) ->
(forall a, PA a -> exists PB0, PF0 a PB0) ->
(BindSpace p PA PF b <-> BindSpace p PA PF0 b).
@ -240,7 +241,7 @@ Proof.
hauto lq:on rew:off.
Qed.
Lemma InterpExt_Join n i I (A B : Tm n) PA PB :
Lemma InterpExt_Join i I (A B : Tm 0) PA PB :
A i ;; I PA ->
B i ;; I PB ->
join A B ->
@ -280,7 +281,7 @@ Proof.
exfalso.
eauto using join_univ_pi_contra.
+ move => m _ [/RPars_join h0 + h1].
have /join_univ_inj {h0 h1} ? : join (Univ j : Tm n) (Univ m) by eauto using join_transitive.
have /join_univ_inj {h0 h1} ? : join (Univ j : Tm 0) (Univ m) by eauto using join_transitive.
subst.
move /InterpExt_Univ_inv. firstorder.
- move => A A0 PA h.
@ -288,34 +289,43 @@ Proof.
eauto using join_transitive.
Qed.
Lemma InterpUniv_Bind_inv n p i (A : Tm n) B P
Lemma InterpUniv_Bind_inv p i (A : Tm 0) B P
(h : TBind p A B i P) :
exists (PA : Tm n -> Prop) (PF : Tm n -> (Tm n -> Prop) -> Prop),
exists (PA : Tm 0 -> Prop) (PF : Tm 0 -> (Tm 0 -> Prop) -> Prop),
A i PA /\
(forall a, PA a -> exists PB, PF a PB) /\
(forall a PB, PF a PB -> subst_Tm (scons a VarTm) B i PB) /\
P = BindSpace p PA PF.
Proof. hauto l:on use:InterpExt_Bind_inv rew:db:InterpUniv. Qed.
Lemma InterpUniv_Univ_inv n i j P
(h : @Univ n j i P) :
P = (fun (A : Tm n) => exists PA, A j PA) /\ j < i.
Lemma InterpUniv_Univ_inv i j P
(h : Univ j i P) :
P = (fun (A : Tm 0) => exists PA, A j PA) /\ j < i.
Proof. hauto l:on use:InterpExt_Univ_inv rew:db:InterpUniv. Qed.
Lemma InterpExt_Functional n i I (A B : Tm n) PA PB :
Lemma InterpExt_Functional i I (A B : Tm 0) PA PB :
A i ;; I PA ->
A i ;; I PB ->
PA = PB.
Proof. hauto use:InterpExt_Join, join_refl. Qed.
Lemma InterpUniv_Functional n i (A B : Tm n) PA PB :
Lemma InterpUniv_Functional i (A : Tm 0) PA PB :
A i PA ->
A i PB ->
PA = PB.
Proof. hauto use:InterpExt_Functional rew:db:InterpUniv. Qed.
Lemma InterpExt_Bind_inv_nopf n i I p A B P (h : TBind p A B i ;; I P) :
exists (PA : Tm n -> Prop),
Lemma InterpUniv_Functional' i j A PA PB :
A i PA ->
A j PB ->
PA = PB.
Proof.
have : i = j \/ i < j \/ j < i by lia.
qauto l:on use:InterpUnivN_cumulative, InterpUniv_Functional.
Qed.
Lemma InterpExt_Bind_inv_nopf i I p A B P (h : TBind p A B i ;; I P) :
exists (PA : Tm 0 -> Prop),
A i ;; I PA /\
(forall a, PA a -> exists PB, subst_Tm (scons a VarTm) B i ;; I PB) /\
P = BindSpace p PA (fun a PB => subst_Tm (scons a VarTm) B i ;; I PB).
@ -336,15 +346,15 @@ Proof.
split; hauto q:on use:InterpExt_Functional.
Qed.
Lemma InterpUniv_Bind_inv_nopf n i p A B P (h : TBind p A B i P) :
exists (PA : Tm n -> Prop),
Lemma InterpUniv_Bind_inv_nopf i p A B P (h : TBind p A B i P) :
exists (PA : Tm 0 -> Prop),
A i PA /\
(forall a, PA a -> exists PB, subst_Tm (scons a VarTm) B i PB) /\
P = BindSpace p PA (fun a PB => subst_Tm (scons a VarTm) B i PB).
Proof. hauto l:on use:InterpExt_Bind_inv_nopf rew:db:InterpUniv. Qed.
Lemma InterpExt_back_clos n i I (A : Tm n) PA :
(forall j, forall a b, (RPar.R a b) -> I n j b -> I n j a) ->
Lemma InterpExt_back_clos i I (A : Tm 0) PA :
(forall j, forall a b, (RPar.R a b) -> I j b -> I j a) ->
A i ;; I PA ->
forall a b, (RPar.R a b) ->
PA b -> PA a.
@ -361,7 +371,7 @@ Proof.
- eauto.
Qed.
Lemma InterpUniv_back_clos n i (A : Tm n) PA :
Lemma InterpUniv_back_clos i (A : Tm 0) PA :
A i PA ->
forall a b, (RPar.R a b) ->
PA b -> PA a.
@ -371,7 +381,7 @@ Proof.
hauto lq:on ctrs:rtc use:InterpUnivN_back_preservation_star.
Qed.
Lemma InterpUniv_back_clos_star n i (A : Tm n) PA :
Lemma InterpUniv_back_clos_star i (A : Tm 0) PA :
A i PA ->
forall a b, rtc RPar.R a b ->
PA b -> PA a.
@ -381,10 +391,10 @@ Proof.
hauto lq:on use:InterpUniv_back_clos.
Qed.
Definition ρ_ok {n} Γ (ρ : fin n -> Tm n) := forall i m PA,
Γ i m PA -> PA (ρ i).
Definition ρ_ok {n} Γ (ρ : fin n -> Tm 0) := forall i m PA,
subst_Tm ρ (Γ i) m PA -> PA (ρ i).
Definition SemWt {n} Γ (a A : Tm n) := forall ρ, ρ_ok Γ ρ -> forall (i : fin n), exists m PA, subst_Tm ρ (Γ i) m PA.
Definition SemWt {n} Γ (a A : Tm n) := forall ρ, ρ_ok Γ ρ -> exists m PA, subst_Tm ρ A m PA /\ PA (subst_Tm ρ a).
Notation "Γ ⊨ a ∈ A" := (SemWt Γ a A) (at level 70).
(* Semantic context wellformedness *)
@ -398,4 +408,46 @@ Proof. rewrite /ρ_ok. inversion i; subst. Qed.
Lemma ρ_ok_cons n i (Γ : fin n -> Tm n) ρ a PA A :
subst_Tm ρ A i PA -> PA a ->
ρ_ok Γ ρ ->
ρ_ok (funcomp (ren_Tm shift) (scons A Γ)) (funcomp (ren_Tm shift) (scons a ρ)).
ρ_ok (funcomp (ren_Tm shift) (scons A Γ)) ((scons a ρ)).
Proof.
move => h0 h1 h2.
rewrite /ρ_ok.
move => j.
destruct j as [j|].
- move => m PA0. asimpl => ?.
firstorder.
- move => m PA0. asimpl => h3.
have ? : PA0 = PA by eauto using InterpUniv_Functional'.
by subst.
Qed.
Definition renaming_ok {n m} (Γ : fin n -> Tm n) (Δ : fin m -> Tm m) (ξ : fin m -> fin n) :=
forall (i : fin m), ren_Tm ξ (Δ i) = Γ (ξ i).
Lemma ρ_ok_renaming n m (Γ : fin n -> Tm n) ρ :
forall (Δ : fin m -> Tm m) ξ,
renaming_ok Γ Δ ξ ->
ρ_ok Γ ρ ->
ρ_ok Δ (funcomp ρ ξ).
Proof.
move => Δ ξ hρ.
rewrite /ρ_ok => i m' PA.
rewrite /renaming_ok in .
rewrite /ρ_ok in hρ.
move => h.
rewrite /funcomp.
apply hρ with (m := m').
move : h. rewrite -.
by asimpl.
Qed.
Lemma renaming_SemWt {n} Γ a A :
Γ a A ->
forall {m} Δ (ξ : fin n -> fin m),
renaming_ok Δ Γ ξ ->
Δ ren_Tm ξ a ren_Tm ξ A.
Proof.
rewrite /SemWt => h m Δ ξ ρ hρ.
have /h hρ' : (ρ_ok Γ (funcomp ρ ξ)) by eauto using ρ_ok_renaming.
hauto q:on solve+:(by asimpl).
Qed.