Prove some simple soundness cases of subtyping

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Yiyun Liu 2025-02-17 21:43:21 -05:00
parent 067ae89b1d
commit 735c7f2046
2 changed files with 152 additions and 0 deletions

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@ -657,6 +657,18 @@ Proof.
hauto lq:on use:Sub.bind_univ_noconf.
Qed.
Lemma T_AbsUniv_Imp' n Γ (a : PTm (S n)) i :
Γ PAbs a PUniv i -> False.
Proof.
hauto lq:on use:synsub_to_usub, Sub.bind_univ_noconf, Abs_Inv.
Qed.
Lemma T_PairUniv_Imp' n Γ (a b : PTm n) i :
Γ PPair a b PUniv i -> False.
Proof.
hauto lq:on use:synsub_to_usub, Sub.bind_univ_noconf, Pair_Inv.
Qed.
Lemma T_AbsBind_Imp n Γ a p A0 B0 (U : PTm n) :
Γ PAbs a U ->
Γ PBind p A0 B0 U ->
@ -1397,6 +1409,24 @@ Combined Scheme coqleq_mutual from coqleq_ind, coqleq_r_ind.
Definition salgo_metric {n} k (a b : PTm n) :=
exists i j va vb, nsteps LoRed.R i a va /\ nsteps LoRed.R j b vb /\ nf va /\ nf vb /\ ESub.R va vb /\ size_PTm va + size_PTm vb + i + j <= k.
Lemma salgo_metric_algo_metric n k (a b : PTm n) :
ishne a \/ ishne b ->
salgo_metric k a b ->
algo_metric k a b.
Proof.
move => h.
move => [i][j][va][vb][hva][hvb][nva][nvb][hS]sz.
rewrite/ESub.R in hS.
move : hS => [va'][vb'][h0][h1]h2.
suff : va' = vb' by sauto lq:on.
have {}hva : rtc RERed.R a va by hauto lq:on use:@relations.rtc_nsteps, REReds.FromRReds, LoReds.ToRReds.
have {}hvb : rtc RERed.R b vb by hauto lq:on use:@relations.rtc_nsteps, REReds.FromRReds, LoReds.ToRReds.
apply REReds.FromEReds in h0, h1.
have : ishne va' \/ ishne vb' by
hauto lq:on rew:off use:@relations.rtc_transitive, REReds.hne_preservation.
hauto lq:on use:Sub1.hne_refl.
Qed.
Lemma coqleq_sound_mutual : forall n,
(forall (a b : PTm n), a b -> forall Γ i, Γ a PUniv i -> Γ b PUniv i -> Γ a b ) /\
(forall (a b : PTm n), a b -> forall Γ i, Γ a PUniv i -> Γ b PUniv i -> Γ a b ).
@ -1426,3 +1456,111 @@ Proof.
suff : Γ a' b' by eauto using Su_Transitive.
eauto using HReds.preservation.
Qed.
Lemma salgo_metric_case n k (a b : PTm n) :
salgo_metric k a b ->
(ishf a \/ ishne a) \/ exists k' a', HRed.R a a' /\ salgo_metric k' a' b /\ k' < k.
Proof.
move=>[i][j][va][vb][h0] [h1][h2][h3][[v [h4 h5]]] h6.
case : a h0 => //=; try firstorder.
- inversion h0 as [|A B C D E F]; subst.
hauto qb:on use:ne_hne.
inversion E; subst => /=.
+ hauto lq:on use:HRed.AppAbs unfold:algo_metric solve+:lia.
+ hauto q:on ctrs:HRed.R use: hf_hred_lored unfold:algo_metric solve+:lia.
+ sfirstorder qb:on use:ne_hne.
- inversion h0 as [|A B C D E F]; subst.
hauto qb:on use:ne_hne.
inversion E; subst => /=.
+ hauto lq:on use:HRed.ProjPair unfold:algo_metric solve+:lia.
+ hauto q:on ctrs:HRed.R use: hf_hred_lored unfold:algo_metric solve+:lia.
Qed.
Lemma CLE_HRedL n (a a' b : PTm n) :
HRed.R a a' ->
a' b ->
a b.
Proof.
hauto lq:on ctrs:rtc, CoqLEq_R inv:CoqLEq_R.
Qed.
Lemma CLE_HRedR n (a a' b : PTm n) :
HRed.R a a' ->
b a' ->
b a.
Proof.
hauto lq:on ctrs:rtc, CoqLEq_R inv:CoqLEq_R.
Qed.
Lemma algo_metric_caseR n k (a b : PTm n) :
salgo_metric k a b ->
(ishf b \/ ishne b) \/ exists k' b', HRed.R b b' /\ salgo_metric k' a b' /\ k' < k.
Proof.
move=>[i][j][va][vb][h0] [h1][h2][h3][[v [h4 h5]]] h6.
case : b h1 => //=; try by firstorder.
- inversion 1 as [|A B C D E F]; subst.
hauto qb:on use:ne_hne.
inversion E; subst => /=.
+ hauto q:on use:HRed.AppAbs unfold:salgo_metric solve+:lia.
+ hauto q:on ctrs:HRed.R use: hf_hred_lored unfold:salgo_metric solve+:lia.
+ sfirstorder qb:on use:ne_hne.
- inversion 1 as [|A B C D E F]; subst.
hauto qb:on use:ne_hne.
inversion E; subst => /=.
+ hauto lq:on use:HRed.ProjPair unfold:algo_metric solve+:lia.
+ hauto q:on ctrs:HRed.R use: hf_hred_lored unfold:algo_metric solve+:lia.
Qed.
Lemma salgo_metric_sub n k (a b : PTm n) :
salgo_metric k a b ->
Sub.R a b.
Proof.
rewrite /algo_metric.
move => [i][j][va][vb][h0][h1][h2][h3][[va' [vb' [hva [hvb hS]]]]]h5.
have {}h0 : rtc LoRed.R a va by hauto lq:on use:@relations.rtc_nsteps.
have {}h1 : rtc LoRed.R b vb by hauto lq:on use:@relations.rtc_nsteps.
apply REReds.FromEReds in hva,hvb.
apply LoReds.ToRReds in h0,h1.
apply REReds.FromRReds in h0,h1.
rewrite /Sub.R. exists va', vb'. sfirstorder use:@relations.rtc_transitive.
Qed.
Lemma coqleq_complete' n k (a b : PTm n) :
salgo_metric k a b -> (forall Γ i, Γ a PUniv i -> Γ b PUniv i -> a b).
Proof.
move : k n a b.
elim /Wf_nat.lt_wf_ind.
move => n ih.
move => k a b /[dup] h /salgo_metric_case.
(* Cases where a and b can take steps *)
case; cycle 1.
move : k a b h.
qauto l:on use:HRed.preservation, CLE_HRedL, hred_hne.
case /algo_metric_caseR : (h); cycle 1.
qauto l:on use:HRed.preservation, CLE_HRedR, hred_hne.
(* Cases where neither a nor b can take steps *)
case => fb; case => fa.
- case : a fa h => //=; try hauto depth:1 lq:on use:T_AbsUniv_Imp', T_PairUniv_Imp'.
+ case : b fb => //=; try hauto depth:1 lq:on use:T_AbsUniv_Imp', T_PairUniv_Imp'.
* move => p0 A0 B0 _ p1 A1 B1 _.
move => h.
have ? : p1 = p0 by
hauto lq:on rew:off use:salgo_metric_sub, Sub.bind_inj.
subst.
case : p0 h => //=; admit.
* hauto lq:on use:salgo_metric_sub, Sub.bind_univ_noconf.
+ case : b fb => //=; try hauto depth:1 lq:on use:T_AbsUniv_Imp', T_PairUniv_Imp'.
* hauto lq:on use:salgo_metric_sub, Sub.univ_bind_noconf.
* move => *. econstructor; eauto using rtc_refl.
hauto lq:on use:salgo_metric_sub, Sub.univ_inj, CLE_UnivCong.
(* Both cases are impossible *)
- admit.
- admit.
- move => Γ i ha hb.
econstructor; eauto using rtc_refl.
apply CLE_NeuNeu. move {ih}.
have {}h : algo_metric n a b by
hauto lq:on use:salgo_metric_algo_metric.
eapply coqeq_complete'; eauto.
Admitted.

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@ -2620,6 +2620,10 @@ Module Sub1.
R a b -> R (subst_PTm ρ a) (subst_PTm ρ b).
Proof. move => h. move : m ρ. elim : n a b /h; hauto lq:on ctrs:R. Qed.
Lemma hne_refl n (a b : PTm n) :
ishne a \/ ishne b -> R a b -> a = b.
Proof. hauto q:on inv:R. Qed.
End Sub1.
Module Sub.
@ -2628,6 +2632,16 @@ Module Sub.
Lemma refl n (a : PTm n) : R a a.
Proof. sfirstorder use:@rtc_refl unfold:R. Qed.
Lemma ToJoin n (a b : PTm n) :
ishne a \/ ishne b ->
R a b ->
DJoin.R a b.
Proof.
move => h [c][d][h0][h1]h2.
have : ishne c \/ ishne d by hauto q:on use:REReds.hne_preservation.
hauto lq:on rew:off use:Sub1.hne_refl.
Qed.
Lemma transitive n (a b c : PTm n) : SN b -> R a b -> R b c -> R a c.
Proof.
rewrite /R.