sp-eta-postpone/theories/logrel.v

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Require Import Autosubst2.core Autosubst2.fintype Autosubst2.syntax.
Require Import common fp_red.
From Hammer Require Import Tactics.
From Equations Require Import Equations.
Require Import ssreflect ssrbool.
Require Import Logic.PropExtensionality (propositional_extensionality).
From stdpp Require Import relations (rtc(..), rtc_subrel).
Import Psatz.
Require Import Cdcl.Itauto.
Definition ProdSpace {n} (PA : PTm n -> Prop)
(PF : PTm n -> (PTm n -> Prop) -> Prop) b : Prop :=
forall a PB, PA a -> PF a PB -> PB (PApp b a).
Definition SumSpace {n} (PA : PTm n -> Prop)
(PF : PTm n -> (PTm n -> Prop) -> Prop) t : Prop :=
(exists v, rtc TRedSN t v /\ SNe v) \/ exists a b, rtc TRedSN t (PPair a b) /\ PA a /\ (forall PB, PF a PB -> PB b).
Definition BindSpace {n} p := if p is PPi then @ProdSpace n else SumSpace.
Reserved Notation "⟦ A ⟧ i ;; I ↘ S" (at level 70).
Inductive InterpExt {n} i (I : nat -> PTm n -> Prop) : PTm n -> (PTm n -> Prop) -> Prop :=
| InterpExt_Ne A :
SNe A ->
A i ;; I (fun a => exists v, rtc TRedSN a v /\ SNe v)
| InterpExt_Bind p A B PA PF :
A i ;; I PA ->
(forall a, PA a -> exists PB, PF a PB) ->
(forall a PB, PF a PB -> subst_PTm (scons a VarPTm) B i ;; I PB) ->
PBind p A B i ;; I BindSpace p PA PF
| InterpExt_Univ j :
j < i ->
PUniv j i ;; I (I j)
| InterpExt_Step A A0 PA :
TRedSN A A0 ->
A0 i ;; I PA ->
A i ;; I PA
where "⟦ A ⟧ i ;; I ↘ S" := (InterpExt i I A S).
Lemma InterpExt_Univ' n i I j (PF : PTm n -> Prop) :
PF = I j ->
j < i ->
PUniv j i ;; I PF.
Proof. hauto lq:on ctrs:InterpExt. Qed.
Infix "<?" := Compare_dec.lt_dec (at level 60).
Equations InterpUnivN n (i : nat) : PTm n -> (PTm n -> Prop) -> Prop by wf i lt :=
InterpUnivN n i := @InterpExt n i
(fun j A =>
match j <? i with
| left _ => exists PA, InterpUnivN n j A PA
| right _ => False
end).
Arguments InterpUnivN {n}.
Lemma InterpExt_lt_impl n i I I' A (PA : PTm n -> Prop) :
(forall j, j < i -> I j = I' j) ->
A i ;; I PA ->
A i ;; I' PA.
Proof.
move => hI h.
elim : A PA /h.
- hauto q:on ctrs:InterpExt.
- hauto lq:on rew:off ctrs:InterpExt.
- hauto q:on ctrs:InterpExt.
- hauto lq:on ctrs:InterpExt.
Qed.
Lemma InterpExt_lt_eq n i I I' A (PA : PTm n -> 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' 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 j (A : PTm n) => exists PA, A j PA).
Proof.
simp InterpUnivN.
extensionality A. extensionality PA.
set I0 := (fun _ => _).
set I1 := (fun _ => _).
apply InterpExt_lt_eq.
hauto q:on.
Qed.
#[export]Hint Rewrite @InterpUnivN_nolt : InterpUniv.
Lemma InterpUniv_ind
: forall n (P : nat -> PTm n -> (PTm n -> Prop) -> Prop),
(forall i (A : PTm n), SNe A -> P i A (fun a : PTm n => exists v : PTm n, rtc TRedSN a v /\ SNe v)) ->
(forall i (p : BTag) (A : PTm n) (B : PTm (S n)) (PA : PTm n -> Prop)
(PF : PTm n -> (PTm n -> Prop) -> Prop),
A i PA ->
P i A PA ->
(forall a : PTm n, PA a -> exists PB : PTm n -> Prop, PF a PB) ->
(forall (a : PTm n) (PB : PTm n -> Prop), PF a PB -> subst_PTm (scons a VarPTm) B i PB) ->
(forall (a : PTm n) (PB : PTm n -> Prop), PF a PB -> P i (subst_PTm (scons a VarPTm) B) PB) ->
P i (PBind p A B) (BindSpace p PA PF)) ->
(forall i j : nat, j < i -> (forall A PA, A j PA -> P j A PA) -> P i (PUniv j) (fun A => exists PA, A j PA)) ->
(forall i (A A0 : PTm n) (PA : PTm n -> Prop), TRedSN A A0 -> A0 i PA -> P i A0 PA -> P i A PA) ->
forall i (p : PTm n) (P0 : PTm n -> Prop), p i P0 -> P i p P0.
Proof.
move => n P hSN hBind hUniv hRed.
elim /Wf_nat.lt_wf_ind => i ih . simp InterpUniv.
move => A PA. move => h. set I := fun _ => _ in h.
elim : A PA / h; rewrite -?InterpUnivN_nolt; eauto.
Qed.
Derive Dependent Inversion iinv with (forall n i I (A : PTm n) PA, InterpExt i I A PA) Sort Prop.
Lemma InterpUniv_Ne n i (A : PTm n) :
SNe A ->
A i (fun a => exists v, rtc TRedSN a v /\ SNe v).
Proof. simp InterpUniv. apply InterpExt_Ne. Qed.
Lemma InterpUniv_Bind n i p A B PA PF :
A : PTm n i PA ->
(forall a, PA a -> exists PB, PF a PB) ->
(forall a PB, PF a PB -> subst_PTm (scons a VarPTm) B i PB) ->
PBind p A B i BindSpace p PA PF.
Proof. simp InterpUniv. apply InterpExt_Bind. Qed.
Lemma InterpUniv_Univ n i j :
j < i -> PUniv j : PTm n i (fun A => exists PA, A j PA).
Proof.
simp InterpUniv. simpl.
apply InterpExt_Univ'. by simp InterpUniv.
Qed.
Lemma InterpUniv_Step i n A A0 PA :
TRedSN A A0 ->
A0 : PTm n i PA ->
A i PA.
Proof. simp InterpUniv. apply InterpExt_Step. Qed.
#[export]Hint Resolve InterpUniv_Bind InterpUniv_Step InterpUniv_Ne InterpUniv_Univ : InterpUniv.
Lemma InterpExt_cumulative n i j I (A : PTm n) PA :
i <= j ->
A i ;; I PA ->
A j ;; I PA.
Proof.
move => h h0.
elim : A PA /h0;
hauto l:on ctrs:InterpExt solve+:(by lia).
Qed.
Lemma InterpUniv_cumulative n i (A : PTm n) PA :
A i PA -> forall j, i <= j ->
A j PA.
Proof.
hauto l:on rew:db:InterpUniv use:InterpExt_cumulative.
Qed.
Definition CR {n} (P : PTm n -> Prop) :=
(forall a, P a -> SN a) /\
(forall a, SNe a -> P a).
Lemma N_Exps n (a b : PTm n) :
rtc TRedSN a b ->
SN b ->
SN a.
Proof.
induction 1; eauto using N_Exp.
Qed.
Lemma adequacy : forall i n A PA,
A : PTm n i PA ->
CR PA /\ SN A.
Proof.
move => + n. apply : InterpUniv_ind.
- hauto l:on use:N_Exps ctrs:SN,SNe.
- move => i p A B PA PF hPA [ihA0 ihA1] hTot hRes ihPF.
have hb : PA PBot by hauto q:on ctrs:SNe.
have hb' : SN PBot by hauto q:on ctrs:SN, SNe.
rewrite /CR.
repeat split.
+ case : p =>//=.
* rewrite /ProdSpace.
qauto use:SN_AppInv unfold:CR.
* hauto q:on unfold:SumSpace use:N_SNe, N_Pair,N_Exps.
+ move => a ha.
case : p=>/=.
* rewrite /ProdSpace => a0 *.
suff : SNe (PApp a a0) by sfirstorder.
hauto q:on use:N_App.
* sfirstorder.
+ apply N_Bind=>//=.
have : SN (PApp (PAbs B) PBot).
apply : N_Exp; eauto using N_β.
hauto lq:on.
qauto l:on use:SN_AppInv, SN_NoForbid.P_AbsInv.
- hauto l:on ctrs:InterpExt rew:db:InterpUniv.
- hauto l:on ctrs:SN unfold:CR.
Qed.
Lemma InterpUniv_Steps i n A A0 PA :
rtc TRedSN A A0 ->
A0 : PTm n i PA ->
A i PA.
Proof. induction 1; hauto l:on use:InterpUniv_Step. Qed.
Lemma InterpUniv_back_clos n i (A : PTm n) PA :
A i PA ->
forall a b, TRedSN a b ->
PA b -> PA a.
Proof.
move : i A PA . apply : InterpUniv_ind; eauto.
- hauto q:on ctrs:rtc.
- move => i p A B PA PF hPA ihPA hTot hRes ihPF a b hr.
case : p => //=.
+ rewrite /ProdSpace.
move => hba a0 PB ha hPB.
suff : TRedSN (PApp a a0) (PApp b a0) by hauto lq:on.
apply N_AppL => //=.
hauto q:on use:adequacy.
+ hauto lq:on ctrs:rtc unfold:SumSpace.
- hauto l:on use:InterpUniv_Step.
Qed.
Lemma InterpUniv_back_closs n i (A : PTm n) PA :
A i PA ->
forall a b, rtc TRedSN a b ->
PA b -> PA a.
Proof.
induction 2; hauto lq:on ctrs:rtc use:InterpUniv_back_clos.
Qed.
Lemma InterpUniv_case n i (A : PTm n) PA :
A i PA ->
exists H, rtc TRedSN A H /\ H i PA /\ (SNe H \/ isbind H \/ isuniv H).
Proof.
move : i A PA. apply InterpUniv_ind => //=.
hauto lq:on ctrs:rtc use:InterpUniv_Ne.
hauto l:on use:InterpUniv_Bind.
hauto l:on use:InterpUniv_Univ.
hauto lq:on ctrs:rtc.
Qed.
Lemma redsn_preservation_mutual n :
(forall (a : PTm n) (s : SNe a), forall b, TRedSN a b -> False) /\
(forall (a : PTm n) (s : SN a), forall b, TRedSN a b -> SN b) /\
(forall (a b : PTm n) (_ : TRedSN a b), forall c, TRedSN a c -> b = c).
Proof.
move : n. apply sn_mutual; sauto lq:on rew:off.
Qed.
Lemma redsns_preservation : forall n a b, @SN n a -> rtc TRedSN a b -> SN b.
Proof. induction 2; sfirstorder use:redsn_preservation_mutual ctrs:rtc. Qed.
#[export]Hint Resolve Sub.sne_bind_noconf Sub.sne_univ_noconf Sub.bind_univ_noconf
Sub.bind_sne_noconf Sub.univ_sne_noconf Sub.univ_bind_noconf: noconf.
Lemma InterpUniv_SNe_inv n i (A : PTm n) PA :
SNe A ->
A i PA ->
PA = (fun a => exists v, rtc TRedSN a v /\ SNe v).
Proof.
simp InterpUniv.
hauto lq:on rew:off inv:InterpExt,SNe use:redsn_preservation_mutual.
Qed.
Lemma InterpUniv_Bind_inv n i p A B S :
PBind p A B i S -> exists PA PF,
A : PTm n i PA /\
(forall a, PA a -> exists PB, PF a PB) /\
(forall a PB, PF a PB -> subst_PTm (scons a VarPTm) B i PB) /\
S = BindSpace p PA PF.
Proof. simp InterpUniv.
inversion 1; try hauto inv:SNe q:on use:redsn_preservation_mutual.
rewrite -!InterpUnivN_nolt.
sauto lq:on.
Qed.
Lemma InterpUniv_Univ_inv n i j S :
PUniv j : PTm n i S ->
S = (fun A => exists PA, A j PA) /\ j < i.
Proof.
simp InterpUniv. inversion 1;
try hauto inv:SNe use:redsn_preservation_mutual.
rewrite -!InterpUnivN_nolt. sfirstorder.
subst. hauto lq:on inv:TRedSN.
Qed.
Lemma bindspace_iff n p (PA : PTm n -> Prop) PF PF0 b :
(forall (a : PTm n) (PB PB0 : PTm n -> Prop), PA a -> 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).
Proof.
rewrite /BindSpace => h hPF hPF0.
case : p => /=.
- rewrite /ProdSpace.
split.
move => h1 a PB ha hPF'.
specialize hPF with (1 := ha).
specialize hPF0 with (1 := ha).
sblast.
move => ? a PB ha.
specialize hPF with (1 := ha).
specialize hPF0 with (1 := ha).
sblast.
- rewrite /SumSpace.
hauto lq:on rew:off.
Qed.
Lemma InterpUniv_Sub' n i (A B : PTm n) PA PB :
A i PA ->
B i PB ->
((Sub.R A B -> forall x, PA x -> PB x) /\
(Sub.R B A -> forall x, PB x -> PA x)).
Proof.
move => hA.
move : i A PA hA B PB.
apply : InterpUniv_ind.
- move => i A hA B PB hPB. split.
+ move => hAB a ha.
have [? ?] : SN B /\ SN A by hauto l:on use:adequacy.
move /InterpUniv_case : hPB.
move => [H [/DJoin.FromRedSNs h [h1 h0]]].
have {h}{}hAB : Sub.R A H by qauto l:on use:Sub.FromJoin, DJoin.symmetric, Sub.transitive.
have {}h0 : SNe H.
suff : ~ isbind H /\ ~ isuniv H by itauto.
move : hA hAB. clear. hauto lq:on db:noconf.
move : InterpUniv_SNe_inv h1 h0. repeat move/[apply]. move => ?. subst.
tauto.
+ move => hAB a ha.
have [? ?] : SN B /\ SN A by hauto l:on use:adequacy.
move /InterpUniv_case : hPB.
move => [H [/DJoin.FromRedSNs h [h1 h0]]].
have {h}{}hAB : Sub.R H A by qauto l:on use:Sub.FromJoin, DJoin.symmetric, Sub.transitive.
have {}h0 : SNe H.
suff : ~ isbind H /\ ~ isuniv H by itauto.
move : hAB hA h0. clear. hauto lq:on db:noconf.
move : InterpUniv_SNe_inv h1 h0. repeat move/[apply]. move => ?. subst.
tauto.
- move => i p A B PA PF hPA ihPA hTot hRes ihPF U PU hU. split.
+ have hU' : SN U by hauto l:on use:adequacy.
move /InterpUniv_case : hU => [H [/DJoin.FromRedSNs h [h1 h0]]] hU.
have {hU} {}h : Sub.R (PBind p A B) H \/ Sub.R H (PBind p A B)
by move : hU hU' h; clear; hauto q:on use:Sub.FromJoin, DJoin.symmetric, Sub.transitive.
have{h0} : isbind H.
suff : ~ SNe H /\ ~ isuniv H by itauto.
have : isbind (PBind p A B) by scongruence.
hauto l:on db:noconf.
admit.
case : H h1 h => //=.
move => p0 A0 B0 h0. /DJoin.bind_inj.
move => [? [hA hB]] _. subst.
move /InterpUniv_Bind_inv : h0.
move => [PA0][PF0][hPA0][hTot0][hRes0 ?]. subst.
have ? : PA0 = PA by qauto l:on. subst.
have : forall a PB PB', PA a -> PF a PB -> PF0 a PB' -> PB = PB'.
move => a PB PB' ha hPB hPB'. apply : ihPF; eauto.
by apply DJoin.substing.
move => h. extensionality b. apply propositional_extensionality.
hauto l:on use:bindspace_iff.
(* - move => i j jlti ih B PB hPB. *)
(* have ? : SN B by hauto l:on use:adequacy. *)
(* move /InterpUniv_case : hPB => [H [/DJoin.FromRedSNs h [h1 h0]]]. *)
(* move => hj. *)
(* have {hj}{}h : DJoin.R (PUniv j) H by eauto using DJoin.transitive. *)
(* have {h0} : isuniv H. *)
(* suff : ~ SNe H /\ ~ isbind H by tauto. *)
(* hauto l:on use: DJoin.sne_univ_noconf, DJoin.bind_univ_noconf, DJoin.symmetric. *)
(* case : H h1 h => //=. *)
(* move => j' hPB h _. *)
(* have {}h : j' = j by hauto lq:on use: DJoin.univ_inj. subst. *)
(* hauto lq:on use:InterpUniv_Univ_inv. *)
(* - move => i A A0 PA hr hPA ihPA B PB hPB hAB. *)
(* have /DJoin.symmetric ? : DJoin.R A A0 by hauto lq:on rew:off ctrs:rtc use:DJoin.FromRedSNs. *)
(* have ? : SN A0 by hauto l:on use:adequacy. *)
(* have ? : SN A by eauto using N_Exp. *)
(* have : DJoin.R A0 B by eauto using DJoin.transitive. *)
(* eauto. *)
(* Qed. *)
Admitted.
Lemma InterpUniv_Sub n i (A B : PTm n) PA PB :
A i PA ->
B i PB ->
Sub.R A B -> forall x, PA x -> PB x.
Proof.
move : InterpUniv_Sub'. repeat move/[apply].
move => [+ _]. apply.
Qed.
Lemma InterpUniv_Join n i (A B : PTm n) PA PB :
A i PA ->
B i PB ->
DJoin.R A B ->
PA = PB.
Proof.
move => + + /[dup] /Sub.FromJoin + /DJoin.symmetric /Sub.FromJoin.
move : InterpUniv_Sub'; repeat move/[apply]. move => h.
move => h1 h2.
extensionality x.
apply propositional_extensionality.
firstorder.
Qed.
Lemma InterpUniv_Functional n i (A : PTm n) PA PB :
A i PA ->
A i PB ->
PA = PB.
Proof. hauto l:on use:InterpUniv_Join, DJoin.refl. Qed.
Lemma InterpUniv_Join' n i j (A B : PTm n) PA PB :
A i PA ->
B j PB ->
DJoin.R A B ->
PA = PB.
Proof.
have [? ?] : i <= max i j /\ j <= max i j by lia.
move => hPA hPB.
have : A (max i j) PA by eauto using InterpUniv_cumulative.
have : B (max i j) PB by eauto using InterpUniv_cumulative.
eauto using InterpUniv_Join.
Qed.
Lemma InterpUniv_Functional' n i j A PA PB :
A : PTm n i PA ->
A j PB ->
PA = PB.
Proof.
hauto l:on use:InterpUniv_Join', DJoin.refl.
Qed.
Lemma InterpUniv_Bind_inv_nopf n i p A B P (h : PBind p A B i P) :
exists (PA : PTm n -> Prop),
A i PA /\
(forall a, PA a -> exists PB, subst_PTm (scons a VarPTm) B i PB) /\
P = BindSpace p PA (fun a PB => subst_PTm (scons a VarPTm) B i PB).
Proof.
move /InterpUniv_Bind_inv : h.
move => [PA][PF][hPA][hPF][hPF']?. subst.
exists PA. repeat split => //.
- sfirstorder.
- extensionality b.
case : p => /=.
+ extensionality a.
extensionality PB.
extensionality ha.
apply propositional_extensionality.
split.
* move => h hPB. apply h.
have {}/hPF := ha.
move => [PB0 hPB0].
have {}/hPF' := hPB0 => ?.
have : PB = PB0 by hauto l:on use:InterpUniv_Functional.
congruence.
* sfirstorder.
+ rewrite /SumSpace. apply propositional_extensionality.
split; hauto q:on use:InterpUniv_Functional.
Qed.
Definition ρ_ok {n} (Γ : fin n -> PTm n) (ρ : fin n -> PTm 0) := forall i k PA,
subst_PTm ρ (Γ i) k PA -> PA (ρ i).
Definition Γ_eq {n} (Γ Δ : fin n -> PTm n) := forall i, DJoin.R (Γ i) (Δ i).
Definition SemWt {n} Γ (a A : PTm n) := forall ρ, ρ_ok Γ ρ -> exists k PA, subst_PTm ρ A k PA /\ PA (subst_PTm ρ a).
Notation "Γ ⊨ a ∈ A" := (SemWt Γ a A) (at level 70).
Definition SemEq {n} Γ (a b A : PTm n) := DJoin.R a b /\ forall ρ, ρ_ok Γ ρ -> exists k PA, subst_PTm ρ A k PA /\ PA (subst_PTm ρ a) /\ PA (subst_PTm ρ b).
Notation "Γ ⊨ a ≡ b ∈ A" := (SemEq Γ a b A) (at level 70).
Lemma SemEq_SemWt n Γ (a b A : PTm n) : Γ a b A -> Γ a A /\ Γ b A /\ DJoin.R a b.
Proof. hauto lq:on rew:off unfold:SemEq, SemWt. Qed.
Lemma SemWt_SemEq n Γ (a b A : PTm n) : Γ a A -> Γ b A -> (DJoin.R a b) -> Γ a b A.
Proof.
move => ha hb heq. split => //= ρ hρ.
have {}/ha := hρ.
have {}/hb := hρ.
move => [k][PA][hPA]hpb.
move => [k0][PA0][hPA0]hpa.
have : PA = PA0 by hauto l:on use:InterpUniv_Functional'.
hauto lq:on.
Qed.
(* Semantic context wellformedness *)
Definition SemWff {n} Γ := forall (i : fin n), exists j, Γ Γ i PUniv j.
Notation "⊨ Γ" := (SemWff Γ) (at level 70).
Lemma ρ_ok_bot n (Γ : fin n -> PTm n) :
ρ_ok Γ (fun _ => PBot).
Proof.
rewrite /ρ_ok.
hauto q:on use:adequacy ctrs:SNe.
Qed.
Lemma ρ_ok_cons n i (Γ : fin n -> PTm n) ρ a PA A :
subst_PTm ρ A i PA -> PA a ->
ρ_ok Γ ρ ->
ρ_ok (funcomp (ren_PTm 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 => ?.
asimpl.
firstorder.
- move => m PA0. asimpl => h3.
have ? : PA0 = PA by eauto using InterpUniv_Functional'.
by subst.
Qed.
Lemma ρ_ok_cons' n i (Γ : fin n -> PTm n) ρ a PA A Δ :
Δ = (funcomp (ren_PTm shift) (scons A Γ)) ->
subst_PTm ρ A i PA -> PA a ->
ρ_ok Γ ρ ->
ρ_ok Δ (scons a ρ).
Proof. move => ->. apply ρ_ok_cons. Qed.
Lemma ρ_ok_renaming n m (Γ : fin n -> PTm n) ρ :
forall (Δ : fin m -> PTm 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 (k := 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_PTm ξ a ren_PTm 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.
Lemma weakening_Sem n Γ (a : PTm n) A B i
(h0 : Γ B PUniv i)
(h1 : Γ a A) :
funcomp (ren_PTm shift) (scons B Γ) ren_PTm shift a ren_PTm shift A.
Proof.
apply : renaming_SemWt; eauto.
hauto lq:on inv:option unfold:renaming_ok.
Qed.
Lemma SemWt_SN n Γ (a : PTm n) A :
Γ a A ->
SN a /\ SN A.
Proof.
move => h.
have {}/h := ρ_ok_bot _ Γ => h.
have h0 : SN (subst_PTm (fun _ : fin n => (PBot : PTm 0)) A) by hauto l:on use:adequacy.
have h1 : SN (subst_PTm (fun _ : fin n => (PBot : PTm 0)) a)by hauto l:on use:adequacy.
move {h}. hauto l:on use:sn_unmorphing.
Qed.
Lemma SemEq_SN_Join n Γ (a b A : PTm n) :
Γ a b A ->
SN a /\ SN b /\ SN A /\ DJoin.R a b.
Proof. hauto l:on use:SemEq_SemWt, SemWt_SN. Qed.
Lemma SemWt_Univ n Γ (A : PTm n) i :
Γ A PUniv i <->
forall ρ, ρ_ok Γ ρ -> exists S, subst_PTm ρ A i S.
Proof.
rewrite /SemWt.
split.
- hauto lq:on rew:off use:InterpUniv_Univ_inv.
- move => /[swap] ρ /[apply].
move => [PA hPA].
exists (S i). eexists.
split.
+ simp InterpUniv. apply InterpExt_Univ. lia.
+ simpl. eauto.
Qed.
(* Structural laws for Semantic context wellformedness *)
Lemma SemWff_nil : SemWff null.
Proof. case. Qed.
Lemma SemWff_cons n Γ (A : PTm n) i :
Γ ->
Γ A PUniv i ->
(* -------------- *)
funcomp (ren_PTm shift) (scons A Γ).
Proof.
move => h h0.
move => j. destruct j as [j|].
- move /(_ j) : h => [k hk].
exists k. change (PUniv k) with (ren_PTm shift (PUniv k : PTm n)).
eauto using weakening_Sem.
- hauto q:on use:weakening_Sem.
Qed.
(* Semantic typing rules *)
Lemma ST_Var n Γ (i : fin n) :
Γ ->
Γ VarPTm i Γ i.
Proof.
move /(_ i) => [j /SemWt_Univ h].
rewrite /SemWt => ρ /[dup] hρ {}/h [S hS].
exists j, S.
asimpl. firstorder.
Qed.
Lemma InterpUniv_Bind_nopf n p i (A : PTm n) B PA :
A i PA ->
(forall a, PA a -> exists PB, subst_PTm (scons a VarPTm) B i PB) ->
PBind p A B i (BindSpace p PA (fun a PB => subst_PTm (scons a VarPTm) B i PB)).
Proof.
move => h0 h1. apply InterpUniv_Bind => //=.
Qed.
Lemma ST_Bind n Γ i j p (A : PTm n) (B : PTm (S n)) :
Γ A PUniv i ->
funcomp (ren_PTm shift) (scons A Γ) B PUniv j ->
Γ PBind p A B PUniv (max i j).
Proof.
move => /SemWt_Univ h0 /SemWt_Univ h1.
apply SemWt_Univ => ρ hρ.
move /h0 : (hρ){h0} => [S hS].
eexists => /=.
have ? : i <= Nat.max i j by lia.
apply InterpUniv_Bind_nopf; eauto.
- eauto using InterpUniv_cumulative.
- move => *. asimpl. hauto l:on use:InterpUniv_cumulative, ρ_ok_cons.
Qed.
Lemma ST_Abs n Γ (a : PTm (S n)) A B i :
Γ PBind PPi A B (PUniv i) ->
funcomp (ren_PTm shift) (scons A Γ) a B ->
Γ PAbs a PBind PPi A B.
Proof.
rename a into b.
move /SemWt_Univ => + hb ρ hρ.
move /(_ _ hρ) => [PPi hPPi].
exists i, PPi. split => //.
simpl in hPPi.
move /InterpUniv_Bind_inv_nopf : hPPi.
move => [PA [hPA [hTot ?]]]. subst=>/=.
move => a PB ha. asimpl => hPB.
move : ρ_ok_cons (hPA) (hρ) (ha). repeat move/[apply].
move /hb.
intros (m & PB0 & hPB0 & hPB0').
replace PB0 with PB in * by hauto l:on use:InterpUniv_Functional'.
apply : InterpUniv_back_clos; eauto.
apply N_β'. by asimpl.
move : ha hPA. clear. hauto q:on use:adequacy.
Qed.
Lemma ST_App n Γ (b a : PTm n) A B :
Γ b PBind PPi A B ->
Γ a A ->
Γ PApp b a subst_PTm (scons a VarPTm) B.
Proof.
move => hf hb ρ hρ.
move /(_ ρ hρ) : hf; intros (i & PPi & hPi & hf).
move /(_ ρ hρ) : hb; intros (j & PA & hPA & hb).
simpl in hPi.
move /InterpUniv_Bind_inv_nopf : hPi. intros (PA0 & hPA0 & hTot & ?). subst.
have ? : PA0 = PA by eauto using InterpUniv_Functional'. subst.
move : hf (hb). move/[apply].
move : hTot hb. move/[apply].
asimpl. hauto lq:on.
Qed.
Lemma ST_Pair n Γ (a b : PTm n) A B i :
Γ PBind PSig A B (PUniv i) ->
Γ a A ->
Γ b subst_PTm (scons a VarPTm) B ->
Γ PPair a b PBind PSig A B.
Proof.
move /SemWt_Univ => + ha hb ρ hρ.
move /(_ _ hρ) => [PPi hPPi].
exists i, PPi. split => //.
simpl in hPPi.
move /InterpUniv_Bind_inv_nopf : hPPi.
move => [PA [hPA [hTot ?]]]. subst=>/=.
rewrite /SumSpace. right.
exists (subst_PTm ρ a), (subst_PTm ρ b).
split.
- apply rtc_refl.
- move /ha : (hρ){ha}.
move => [m][PA0][h0]h1.
move /hb : (hρ){hb}.
move => [k][PB][h2]h3.
have ? : PA0 = PA by eauto using InterpUniv_Functional'. subst.
split => // PB0.
move : h2. asimpl => *.
have ? : PB0 = PB by eauto using InterpUniv_Functional'. by subst.
Qed.
Lemma N_Projs n p (a b : PTm n) :
rtc TRedSN a b ->
rtc TRedSN (PProj p a) (PProj p b).
Proof. induction 1; hauto lq:on ctrs:rtc, TRedSN. Qed.
Lemma ST_Proj1 n Γ (a : PTm n) A B :
Γ a PBind PSig A B ->
Γ PProj PL a A.
Proof.
move => h ρ /[dup]hρ {}/h [m][PA][/= /InterpUniv_Bind_inv_nopf h0]h1.
move : h0 => [S][h2][h3]?. subst.
move : h1 => /=.
rewrite /SumSpace.
case.
- move => [v [h0 h1]].
have {}h0 : rtc TRedSN (PProj PL (subst_PTm ρ a)) (PProj PL v) by hauto lq:on use:N_Projs.
have {}h1 : SNe (PProj PL v) by hauto lq:on ctrs:SNe.
hauto q:on use:InterpUniv_back_closs,adequacy.
- move => [a0 [b0 [h4 [h5 h6]]]].
exists m, S. split => //=.
have {}h4 : rtc TRedSN (PProj PL (subst_PTm ρ a)) (PProj PL (PPair a0 b0)) by eauto using N_Projs.
have ? : rtc TRedSN (PProj PL (PPair a0 b0)) a0 by hauto q:on ctrs:rtc, TRedSN use:adequacy.
have : rtc TRedSN (PProj PL (subst_PTm ρ a)) a0 by hauto q:on ctrs:rtc use:@relations.rtc_r.
move => h.
apply : InterpUniv_back_closs; eauto.
Qed.
Lemma ST_Proj2 n Γ (a : PTm n) A B :
Γ a PBind PSig A B ->
Γ PProj PR a subst_PTm (scons (PProj PL a) VarPTm) B.
Proof.
move => h ρ hρ.
move : (hρ) => {}/h [m][PA][/= /InterpUniv_Bind_inv_nopf h0]h1.
move : h0 => [S][h2][h3]?. subst.
move : h1 => /=.
rewrite /SumSpace.
case.
- move => h.
move : h => [v [h0 h1]].
have hp : forall p, SNe (PProj p v) by hauto lq:on ctrs:SNe.
have hp' : forall p, rtc TRedSN (PProj p(subst_PTm ρ a)) (PProj p v) by eauto using N_Projs.
have hp0 := hp PL. have hp1 := hp PR => {hp}.
have hp0' := hp' PL. have hp1' := hp' PR => {hp'}.
have : S (PProj PL (subst_PTm ρ a)). apply : InterpUniv_back_closs; eauto. hauto q:on use:adequacy.
move /h3 => [PB]. asimpl => hPB.
do 2 eexists. split; eauto.
apply : InterpUniv_back_closs; eauto. hauto q:on use:adequacy.
- move => [a0 [b0 [h4 [h5 h6]]]].
have h3_dup := h3.
specialize h3 with (1 := h5).
move : h3 => [PB hPB].
have hr : forall p, rtc TRedSN (PProj p (subst_PTm ρ a)) (PProj p (PPair a0 b0)) by hauto l:on use: N_Projs.
have hSN : SN a0 by move : h5 h2; clear; hauto q:on use:adequacy.
have hSN' : SN b0 by hauto q:on use:adequacy.
have hrl : TRedSN (PProj PL (PPair a0 b0)) a0 by hauto lq:on ctrs:TRedSN.
have hrr : TRedSN (PProj PR (PPair a0 b0)) b0 by hauto lq:on ctrs:TRedSN.
exists m, PB.
asimpl. split.
+ have hr' : rtc TRedSN (PProj PL (subst_PTm ρ a)) a0 by hauto l:on use:@relations.rtc_r.
have : S (PProj PL (subst_PTm ρ a)) by hauto lq:on use:InterpUniv_back_closs.
move => {}/h3_dup.
move => [PB0]. asimpl => hPB0.
suff : PB = PB0 by congruence.
move : hPB. asimpl => hPB.
suff : DJoin.R (subst_PTm (scons (PProj PL (subst_PTm ρ a)) ρ) B) (subst_PTm (scons a0 ρ) B).
move : InterpUniv_Join hPB0 hPB; repeat move/[apply]. done.
apply DJoin.cong.
apply DJoin.FromRedSNs.
hauto lq:on ctrs:rtc unfold:BJoin.R.
+ hauto lq:on use:@relations.rtc_r, InterpUniv_back_closs.
Qed.
Lemma ST_Conv' n Γ (a : PTm n) A B i :
Γ a A ->
Γ B PUniv i ->
DJoin.R A B ->
Γ a B.
Proof.
move => ha /SemWt_Univ h h0.
move => ρ hρ.
have {}h0 : DJoin.R (subst_PTm ρ A) (subst_PTm ρ B) by eauto using DJoin.substing.
move /ha : (hρ){ha} => [m [PA [h1 h2]]].
move /h : (hρ){h} => [S hS].
have ? : PA = S by eauto using InterpUniv_Join'. subst.
eauto.
Qed.
Lemma ST_Conv n Γ (a : PTm n) A B i :
Γ a A ->
Γ A B PUniv i ->
Γ a B.
Proof. hauto l:on use:ST_Conv', SemEq_SemWt. Qed.
Lemma SE_Refl n Γ (a : PTm n) A :
Γ a A ->
Γ a a A.
Proof. hauto lq:on unfold:SemWt,SemEq use:DJoin.refl. Qed.
Lemma SE_Symmetric n Γ (a b : PTm n) A :
Γ a b A ->
Γ b a A.
Proof. hauto q:on unfold:SemEq. Qed.
Lemma SE_Transitive n Γ (a b c : PTm n) A :
Γ a b A ->
Γ b c A ->
Γ a c A.
Proof.
move => ha hb.
apply SemEq_SemWt in ha, hb.
have ? : SN b by hauto l:on use:SemWt_SN.
apply SemWt_SemEq; try tauto.
hauto l:on use:DJoin.transitive.
Qed.
Lemma Γ_eq_ρ_ok n Γ Δ (ρ : fin n -> PTm 0) : Γ_eq Γ Δ -> Γ -> ρ_ok Γ ρ -> ρ_ok Δ ρ.
Proof.
move => hΓΔ h.
move => i k PA hPA.
move : . rewrite /SemWff. move /(_ i) => [j].
move => .
rewrite SemWt_Univ in .
have {}/ := h.
move => [S hS].
move /(_ i) in h. suff : PA = S by qauto l:on.
move : InterpUniv_Join' hPA hS. repeat move/[apply].
apply. move /(_ i) /DJoin.symmetric in hΓΔ.
hauto l:on use: DJoin.substing.
Qed.
Lemma Γ_eq_refl n (Γ : fin n -> PTm n) :
Γ_eq Γ Γ.
Proof. sfirstorder use:DJoin.refl. Qed.
Lemma Γ_eq_cons n (Γ Δ : fin n -> PTm n) A B :
DJoin.R A B ->
Γ_eq Γ Δ ->
Γ_eq (funcomp (ren_PTm shift) (scons A Γ)) (funcomp (ren_PTm shift) (scons B Δ)).
Proof.
move => h h0.
move => i.
destruct i as [i|].
rewrite /funcomp. substify. apply DJoin.substing. by asimpl.
rewrite /funcomp.
asimpl. substify. apply DJoin.substing. by asimpl.
Qed.
Lemma Γ_eq_cons' n (Γ : fin n -> PTm n) A B :
DJoin.R A B ->
Γ_eq (funcomp (ren_PTm shift) (scons A Γ)) (funcomp (ren_PTm shift) (scons B Γ)).
Proof. eauto using Γ_eq_refl ,Γ_eq_cons. Qed.
Lemma SE_Bind n Γ i j p (A0 A1 : PTm n) B0 B1 :
Γ ->
Γ A0 A1 PUniv i ->
funcomp (ren_PTm shift) (scons A0 Γ) B0 B1 PUniv j ->
Γ PBind p A0 B0 PBind p A1 B1 PUniv (max i j).
Proof.
move => hA hB.
apply SemEq_SemWt in hA, hB.
apply SemWt_SemEq; last by hauto l:on use:DJoin.BindCong.
hauto l:on use:ST_Bind.
apply ST_Bind; first by tauto.
have hΓ' : funcomp (ren_PTm shift) (scons A1 Γ) by hauto l:on use:SemWff_cons.
move => ρ hρ.
suff : ρ_ok (funcomp (ren_PTm shift) (scons A0 Γ)) ρ by hauto l:on.
move : Γ_eq_ρ_ok hΓ' hρ; repeat move/[apply]. apply.
hauto lq:on use:Γ_eq_cons'.
Qed.
Lemma SE_Abs n Γ (a b : PTm (S n)) A B i :
Γ PBind PPi A B (PUniv i) ->
funcomp (ren_PTm shift) (scons A Γ) a b B ->
Γ PAbs a PAbs b PBind PPi A B.
Proof.
move => hPi /SemEq_SemWt [ha][hb]he.
apply SemWt_SemEq; eauto using DJoin.AbsCong, ST_Abs.
Qed.
Lemma SE_Conv' n Γ (a b : PTm n) A B i :
Γ a b A ->
Γ B PUniv i ->
DJoin.R A B ->
Γ a b B.
Proof.
move /SemEq_SemWt => [ha][hb]he hB hAB.
apply SemWt_SemEq; eauto using ST_Conv'.
Qed.
Lemma SE_Conv n Γ (a b : PTm n) A B i :
Γ a b A ->
Γ A B PUniv i ->
Γ a b B.
Proof.
move => h /SemEq_SemWt [h0][h1]he.
eauto using SE_Conv'.
Qed.
Lemma SBind_inst n Γ p i (A : PTm n) B (a : PTm n) :
Γ a A ->
Γ PBind p A B PUniv i ->
Γ subst_PTm (scons a VarPTm) B PUniv i.
Proof.
move => ha /SemWt_Univ hb.
apply SemWt_Univ.
move => ρ hρ.
have {}/hb := hρ.
asimpl. move => /= [S hS].
move /InterpUniv_Bind_inv_nopf : hS.
move => [PA][hPA][hPF]?. subst.
have {}/ha := hρ.
move => [k][PA0][hPA0]ha.
have ? : PA0 = PA by hauto l:on use:InterpUniv_Functional'. subst.
have {}/hPF := ha.
move => [PB]. asimpl.
hauto lq:on.
Qed.
Lemma SE_Pair n Γ (a0 a1 b0 b1 : PTm n) A B i :
Γ PBind PSig A B (PUniv i) ->
Γ a0 a1 A ->
Γ b0 b1 subst_PTm (scons a0 VarPTm) B ->
Γ PPair a0 b0 PPair a1 b1 PBind PSig A B.
Proof.
move => h /SemEq_SemWt [ha0][ha1]hae /SemEq_SemWt [hb0][hb1]hbe.
apply SemWt_SemEq; eauto using ST_Pair, DJoin.PairCong, SBind_inst, DJoin.cong, ST_Conv', ST_Pair.
Qed.
Lemma SE_Proj1 n Γ (a b : PTm n) A B :
Γ a b PBind PSig A B ->
Γ PProj PL a PProj PL b A.
Proof.
move => /SemEq_SemWt [ha][hb]he.
apply SemWt_SemEq; eauto using DJoin.ProjCong, ST_Proj1.
Qed.
Lemma SE_Proj2 n Γ i (a b : PTm n) A B :
Γ PBind PSig A B (PUniv i) ->
Γ a b PBind PSig A B ->
Γ PProj PR a PProj PR b subst_PTm (scons (PProj PL a) VarPTm) B.
Proof.
move => hS.
move => /SemEq_SemWt [ha][hb]he.
apply SemWt_SemEq; eauto using DJoin.ProjCong, ST_Proj2.
have h : Γ PProj PR b subst_PTm (scons (PProj PL b) VarPTm) B by eauto using ST_Proj2.
apply : ST_Conv'. apply h.
apply : SBind_inst. eauto using ST_Proj1.
eauto.
hauto lq:on use: DJoin.cong, DJoin.ProjCong.
Qed.
Lemma SE_App n Γ i (b0 b1 a0 a1 : PTm n) A B :
Γ PBind PPi A B (PUniv i) ->
Γ b0 b1 PBind PPi A B ->
Γ a0 a1 A ->
Γ PApp b0 a0 PApp b1 a1 subst_PTm (scons a0 VarPTm) B.
Proof.
move => hPi.
move => /SemEq_SemWt [hb0][hb1]hb /SemEq_SemWt [ha0][ha1]ha.
apply SemWt_SemEq; eauto using DJoin.AppCong, ST_App.
apply : ST_Conv'; eauto using ST_App, DJoin.cong, DJoin.symmetric, SBind_inst.
Qed.
Lemma SBind_inv1 n Γ i p (A : PTm n) B :
Γ PBind p A B PUniv i ->
Γ A PUniv i.
move /SemWt_Univ => h. apply SemWt_Univ.
hauto lq:on rew:off use:InterpUniv_Bind_inv.
Qed.
Lemma SE_Bind_Proj1 n Γ p (A0 A1 : PTm n) B0 B1 i :
Γ PBind p A0 B0 PBind p A1 B1 PUniv i ->
Γ A0 A1 PUniv i.
Proof.
move /SemEq_SemWt => [h0][h1]he.
apply SemWt_SemEq; eauto using SBind_inv1.
move /DJoin.bind_inj : he. tauto.
Qed.
Lemma SE_Bind_Proj2 n Γ p (a0 a1 A0 A1 : PTm n) B0 B1 i :
Γ PBind p A0 B0 PBind p A1 B1 PUniv i ->
Γ a0 a1 A0 ->
Γ subst_PTm (scons a0 VarPTm) B0 subst_PTm (scons a1 VarPTm) B1 PUniv i.
Proof.
move /SemEq_SemWt => [hA][hB]/DJoin.bind_inj [_ [h1 h2]] /SemEq_SemWt [ha0][ha1]ha.
move : h2 => [B [h2 h2']].
move : ha => [c [ha ha']].
apply SemWt_SemEq; eauto using SBind_inst.
apply SBind_inst with (p := p) (A := A1); eauto.
apply : ST_Conv'; eauto. hauto l:on use:SBind_inv1.
rewrite /DJoin.R.
eexists. split.
apply : relations.rtc_transitive.
apply REReds.substing. apply h2.
apply REReds.cong.
have : forall i0, rtc RERed.R (scons a0 VarPTm i0) (scons c VarPTm i0) by hauto q:on ctrs:rtc inv:option.
apply.
apply : relations.rtc_transitive. apply REReds.substing; eauto.
apply REReds.cong.
hauto lq:on ctrs:rtc inv:option.
Qed.
Lemma ST_Univ n Γ i j :
i < j ->
Γ PUniv i : PTm n PUniv j.
Proof.
move => ?.
apply SemWt_Univ. move => ρ hρ. eexists. by apply InterpUniv_Univ.
Qed.
#[export]Hint Resolve ST_Var ST_Bind ST_Abs ST_App ST_Pair ST_Proj1 ST_Proj2 ST_Univ ST_Conv
SE_Refl SE_Symmetric SE_Transitive SE_Bind SE_Abs SE_App SE_Proj1 SE_Proj2
SE_Conv SE_Bind_Proj1 SE_Bind_Proj2 SemWff_nil SemWff_cons : sem.