Mcltt.Core.Soundness.LogicalRelation.CoreLemmas

From Coq Require Import Equivalence Morphisms Morphisms_Prop Morphisms_Relations Relation_Definitions RelationClasses.

From Mcltt Require Import LibTactics.
From Mcltt.Core Require Import Base.
From Mcltt.Core.Soundness.LogicalRelation Require Import CoreTactics Definitions.
From Mcltt.Core.Soundness.Weakening Require Export Lemmas.
Import Domain_Notations.

Lemma glu_nat_per_nat : forall Γ M a,
    glu_nat Γ M a ->
    {{ Dom a a per_nat }}.
Proof.
  induction 1; mauto.
Qed.

#[local]
Hint Resolve glu_nat_per_nat : mcltt.

Lemma glu_nat_escape : forall Γ M a,
    glu_nat Γ M a ->
    {{ Γ }} ->
    {{ Γ M : }}.
Proof.
  induction 1; intros;
    try match goal with
    | H : _ |- _ => solve [gen_presup H; mauto]
    end.
  assert {{ Γ w Id : Γ }} by mauto.
  match_by_head (per_bot m m) ltac:(fun H => specialize (H (length Γ)) as [M' []]).
  clear_dups.
  assert {{ Γ M[Id] M' : }} by mauto.
  gen_presups.
  mauto.
Qed.

#[export]
Hint Resolve glu_nat_escape : mcltt.

Lemma glu_nat_resp_ctx_eq : forall Γ M a Δ,
    glu_nat Γ M a ->
    {{ Γ Δ }} ->
    glu_nat Δ M a.
Proof.
  induction 1; intros; mauto.
Qed.

#[local]
Hint Resolve glu_nat_resp_ctx_eq : mcltt.

Add Parametric Morphism : glu_nat
    with signature wf_ctx_eq ==> eq ==> eq ==> iff as glu_ctx_env_sub_morphism_iff1.
Proof.
  split; mauto using glu_nat_resp_ctx_eq.
Qed.

Lemma glu_nat_resp_exp_eq : forall Γ M a,
    glu_nat Γ M a ->
    forall M',
    {{ Γ M M' : }} ->
    glu_nat Γ M' a.
Proof.
  induction 1; intros; mauto 4.
  econstructor; trivial.
  intros.
  transitivity {{{ M[σ] }}}; mauto.
Qed.

#[local]
Hint Resolve glu_nat_resp_exp_eq : mcltt.

Add Parametric Morphism Γ : (glu_nat Γ)
    with signature wf_exp_eq Γ {{{ }}} ==> eq ==> iff as glu_ctx_env_sub_morphism_iff2.
Proof.
  split; mauto using glu_nat_resp_exp_eq.
Qed.

Lemma glu_nat_readback : forall Γ M a,
    glu_nat Γ M a ->
    forall Δ σ M',
      {{ Δ w σ : Γ }} ->
      {{ Rnf a in length Δ M' }} ->
      {{ Δ M[σ] M' : }}.
Proof.
  induction 1; intros; progressive_inversion; gen_presups.
  - transitivity {{{ zero[σ] }}}; mauto 4.
  - assert {{ Δ M'[σ] M0 : }} by mauto 4.
    transitivity {{{ (succ M')[σ] }}}; mauto 3.
    transitivity {{{ succ M'[σ] }}}; mauto 4.
  - mauto 4.
Qed.

#[global]
Ltac simpl_glu_rel :=
  apply_equiv_left;
  repeat invert_glu_rel1;
  apply_equiv_left;
  destruct_all;
  gen_presups.

Lemma glu_univ_elem_univ_lvl : forall i P El a,
    {{ DG a glu_univ_elem i P El }} ->
    forall Γ A,
      {{ Γ A ® P }} ->
      {{ Γ A : Type@i }}.
Proof.
  simpl.
  induction 1 using glu_univ_elem_ind; intros;
    simpl_glu_rel; trivial.
Qed.

Lemma glu_univ_elem_typ_resp_exp_eq : forall i P El a,
    {{ DG a glu_univ_elem i P El }} ->
    forall Γ A A',
      {{ Γ A ® P }} ->
      {{ Γ A A' : Type@i }} ->
      {{ Γ A' ® P }}.
Proof.
  simpl.
  induction 1 using glu_univ_elem_ind; intros;
    simpl_glu_rel; mauto 4.

  split; [trivial |].
  intros.
  transitivity {{{ A[σ] }}}; mauto 4.
Qed.

Add Parametric Morphism i P El a (H : glu_univ_elem i P El a) Γ : (P Γ)
    with signature wf_exp_eq Γ {{{ Type@i }}} ==> iff as glu_univ_elem_typ_morphism_iff1.
Proof.
  split; intros; eapply glu_univ_elem_typ_resp_exp_eq; mauto 2.
Qed.

Lemma glu_univ_elem_trm_resp_typ_exp_eq : forall i P El a,
    {{ DG a glu_univ_elem i P El }} ->
    forall Γ M A m A',
      {{ Γ M : A ® m El }} ->
      {{ Γ A A' : Type@i }} ->
      {{ Γ M : A' ® m El }}.
Proof.
  simpl.
  induction 1 using glu_univ_elem_ind; intros;
    simpl_glu_rel; repeat split; intros; mauto 3;
    [firstorder | | transitivity {{{ A[σ] }}}; mauto 4 | assert {{ Δ A[σ] A'[σ] : Type@i }}; mauto 3].

  econstructor; mauto 3.
Qed.

Add Parametric Morphism i P El a (H : glu_univ_elem i P El a) Γ : (El Γ)
    with signature wf_exp_eq Γ {{{Type@i}}} ==> eq ==> eq ==> iff as glu_univ_elem_trm_morphism_iff1.
Proof.
  split; intros;
    eapply glu_univ_elem_trm_resp_typ_exp_eq;
    mauto 2.
Qed.

Lemma glu_univ_elem_typ_resp_ctx_eq : forall i P El a,
    {{ DG a glu_univ_elem i P El }} ->
    forall Γ A Δ,
      {{ Γ A ® P }} ->
      {{ Γ Δ }} ->
      {{ Δ A ® P }}.
Proof.
  simpl.
  induction 1 using glu_univ_elem_ind; intros;
    simpl_glu_rel; mauto 2;
    econstructor; mauto 4.
Qed.

Add Parametric Morphism i P El a (H : glu_univ_elem i P El a) : P
    with signature wf_ctx_eq ==> eq ==> iff as glu_univ_elem_typ_morphism_iff2.
Proof.
  intros. split; intros;
    eapply glu_univ_elem_typ_resp_ctx_eq;
    mauto 2.
Qed.

Lemma glu_univ_elem_trm_resp_ctx_eq : forall i P El a,
    {{ DG a glu_univ_elem i P El }} ->
    forall Γ A M m Δ,
      {{ Γ M : A ® m El }} ->
      {{ Γ Δ }} ->
      {{ Δ M : A ® m El }}.
Proof.
  simpl.
  induction 1 using glu_univ_elem_ind; intros;
    simpl_glu_rel; mauto 2;
    econstructor; mauto 4 using glu_nat_resp_ctx_eq.

  - split; mauto.
    do 2 eexists.
    split; mauto.
    eapply glu_univ_elem_typ_resp_ctx_eq; mauto.
  - split; mauto 4.
Qed.

Add Parametric Morphism i P El a (H : glu_univ_elem i P El a) : El
    with signature wf_ctx_eq ==> eq ==> eq ==> eq ==> iff as glu_univ_elem_trm_morphism_iff2.
Proof.
  intros. split; intros;
    eapply glu_univ_elem_trm_resp_ctx_eq;
    mauto 2.
Qed.

Lemma glu_nat_resp_wk' : forall Γ M a,
    glu_nat Γ M a ->
    forall Δ σ,
      {{ Γ M : }} ->
      {{ Δ w σ : Γ }} ->
      glu_nat Δ {{{ M[σ] }}} a.
Proof.
  induction 1; intros; gen_presups.
  - econstructor.
    transitivity {{{ zero[σ] }}}; mauto.
  - econstructor; [ |mauto].
    transitivity {{{ (succ M')[σ] }}}; mauto 4.
  - econstructor; trivial.
    intros Δ' τ M' **.
    gen_presups.
    assert {{ Δ' w στ : Γ }} by mauto.
    assert {{ Δ' M[στ] M' : }} by mauto 4.
    transitivity {{{ M[στ] }}}; mauto 4.
Qed.

Lemma glu_nat_resp_wk : forall Γ M a,
    glu_nat Γ M a ->
    forall Δ σ,
      {{ Δ w σ : Γ }} ->
      glu_nat Δ {{{ M[σ] }}} a.
Proof.
  mauto using glu_nat_resp_wk'.
Qed.

#[export]
Hint Resolve glu_nat_resp_wk : mcltt.

Lemma glu_univ_elem_trm_escape : forall i P El a,
    {{ DG a glu_univ_elem i P El }} ->
    forall Γ M A m,
      {{ Γ M : A ® m El }} ->
      {{ Γ M : A }}.
Proof.
  simpl.
  induction 1 using glu_univ_elem_ind; intros;
    simpl_glu_rel; mauto 4.
Qed.

Lemma glu_univ_elem_per_univ : forall i P El a,
    {{ DG a glu_univ_elem i P El }} ->
    {{ Dom a a per_univ i }}.
Proof.
  simpl.
  induction 1 using glu_univ_elem_ind; intros; eexists;
    try solve [per_univ_elem_econstructor; try reflexivity; trivial].

  - subst. eapply per_univ_elem_core_univ'; trivial.
    reflexivity.
  - match_by_head per_univ_elem ltac:(fun H => directed invert_per_univ_elem H).
    mauto.
Qed.

#[export]
Hint Resolve glu_univ_elem_per_univ : mcltt.

Lemma glu_univ_elem_per_elem : forall i P El a,
    {{ DG a glu_univ_elem i P El }} ->
    forall Γ M A m R,
      {{ Γ M : A ® m El }} ->
      {{ DF a a per_univ_elem i R }} ->
      {{ Dom m m R }}.
Proof.
  simpl.
  induction 1 using glu_univ_elem_ind; intros;
    match_by_head per_univ_elem ltac:(fun H => directed invert_per_univ_elem H);
    simpl_glu_rel;
    try fold (per_univ j m m);
    mauto 4.

  intros.
  destruct_rel_mod_app.
  destruct_rel_mod_eval.
  functional_eval_rewrite_clear.
  do_per_univ_elem_irrel_assert.

  econstructor; firstorder eauto.
Qed.

Lemma glu_univ_elem_trm_typ : forall i P El a,
    {{ DG a glu_univ_elem i P El }} ->
    forall Γ M A m,
      {{ Γ M : A ® m El }} ->
      {{ Γ A ® P }}.
Proof.
  simpl.
  induction 1 using glu_univ_elem_ind; intros;
    simpl_glu_rel;
    mauto 4.

  econstructor; eauto.
  match_by_head per_univ_elem ltac:(fun H => directed invert_per_univ_elem H).
  intros ? ? N n ? ? equiv_n.
  destruct_rel_mod_eval.
  enough (exists mn : domain, {{ $| m & n |↘ mn }} /\ {{ Δ M[σ] N : OT[σ,,N] ® mn OEl n equiv_n }}) as [? []]; eauto 3.
Qed.

Lemma glu_univ_elem_trm_univ_lvl : forall i P El a,
    {{ DG a glu_univ_elem i P El }} ->
    forall Γ M A m,
      {{ Γ M : A ® m El }} ->
      {{ Γ A : Type@i }}.
Proof.
  intros. eapply glu_univ_elem_univ_lvl; [| eapply glu_univ_elem_trm_typ]; eassumption.
Qed.

Lemma glu_univ_elem_trm_resp_exp_eq : forall i P El a,
    {{ DG a glu_univ_elem i P El }} ->
    forall Γ A M m M',
      {{ Γ M : A ® m El }} ->
      {{ Γ M M' : A }} ->
      {{ Γ M' : A ® m El }}.
Proof.
  simpl.
  induction 1 using glu_univ_elem_ind; intros;
    simpl_glu_rel;
    repeat split; mauto 3.

  - repeat eexists; try split; eauto.
    eapply glu_univ_elem_typ_resp_exp_eq; mauto.

  - econstructor; eauto.
    match_by_head per_univ_elem ltac:(fun H => directed invert_per_univ_elem H).
    intros.
    destruct_rel_mod_eval.
    assert {{ Δ N : IT[σ]}} by eauto using glu_univ_elem_trm_escape.
    assert (exists mn : domain, {{ $| m & n |↘ mn }} /\ {{ Δ M[σ] N : OT[σ,,N] ® mn OEl n equiv_n }}) as [? []] by intuition.
    eexists; split; eauto.
    enough {{ Δ M[σ] N M'[σ] N : OT[σ,,N] }} by eauto.
    assert {{ Γ M M' : Π IT OT }} as Hty by mauto.
    eassert {{ Δ IT[σ] : Type@_ }} by mauto 3.
    eapply wf_exp_eq_sub_cong with (Γ := Δ) in Hty; [| eapply sub_eq_refl; mauto 3].
    autorewrite with mcltt in Hty.
    eapply wf_exp_eq_app_cong with (N := N) (N' := N) in Hty; try pi_univ_level_tac; [|mauto 2].
    autorewrite with mcltt in Hty.
    eassumption.
  - intros.
    enough {{ Δ M[σ] M'[σ] : A[σ] }}; mauto 4.
Qed.

Add Parametric Morphism i P El a (H : glu_univ_elem i P El a) Γ T : (El Γ T)
    with signature wf_exp_eq Γ T ==> eq ==> iff as glu_univ_elem_trm_morphism_iff3.
Proof.
  split; intros;
    eapply glu_univ_elem_trm_resp_exp_eq;
    mauto 2.
Qed.

Lemma glu_univ_elem_core_univ' : forall j i typ_rel el_rel,
    j < i ->
    (typ_rel <∙> univ_glu_typ_pred j i) ->
    (el_rel <∙> univ_glu_exp_pred j i) ->
    {{ DG 𝕌@j glu_univ_elem i typ_rel el_rel }}.
Proof.
  intros.
  unshelve basic_glu_univ_elem_econstructor; mautosolve.
Qed.

#[export]
Hint Resolve glu_univ_elem_core_univ' : mcltt.

Ltac glu_univ_elem_econstructor :=
  eapply glu_univ_elem_core_univ' + basic_glu_univ_elem_econstructor.

Lemma glu_univ_elem_univ_simple_constructor : forall {i},
    glu_univ_elem (S i) (univ_glu_typ_pred i (S i)) (univ_glu_exp_pred i (S i)) d{{{ 𝕌@i }}}.
Proof.
  intros.
  glu_univ_elem_econstructor; mauto; reflexivity.
Qed.

#[export]
Hint Resolve glu_univ_elem_univ_simple_constructor : mcltt.

Ltac rewrite_predicate_equivalence_left :=
  repeat match goal with
    | H : ?R1 <∙> ?R2 |- _ =>
        try setoid_rewrite H;
        (on_all_hyp: fun H' => assert_fails (unify H H'); unmark H; setoid_rewrite H in H');
        let T := type of H in
        fold (id T) in H
    end; unfold id in *.

Ltac rewrite_predicate_equivalence_right :=
  repeat match goal with
    | H : ?R1 <∙> ?R2 |- _ =>
        try setoid_rewrite <- H;
        (on_all_hyp: fun H' => assert_fails (unify H H'); unmark H; setoid_rewrite <- H in H');
        let T := type of H in
        fold (id T) in H
    end; unfold id in *.

Ltac clear_predicate_equivalence :=
  repeat match goal with
    | H : ?R1 <∙> ?R2 |- _ =>
        (unify R1 R2; clear H) + (is_var R1; clear R1 H) + (is_var R2; clear R2 H)
    end.

Ltac apply_predicate_equivalence :=
  clear_predicate_equivalence;
  rewrite_predicate_equivalence_right;
  clear_predicate_equivalence;
  rewrite_predicate_equivalence_left;
  clear_predicate_equivalence.

Simple Morphism instance for glu_univ_elem

Add Parametric Morphism i : (glu_univ_elem i)
    with signature glu_typ_pred_equivalence ==> glu_exp_pred_equivalence ==> eq ==> iff as simple_glu_univ_elem_morphism_iff.
Proof with mautosolve.
  intros P P' ? El El'.
  split; intro Horig; [gen El' P' | gen El P];
    induction Horig using glu_univ_elem_ind; unshelve glu_univ_elem_econstructor;
    try (etransitivity; [symmetry + idtac|]; eassumption); eauto.
Qed.

Morphism instances for neut_glu_*_preds

Add Parametric Morphism i : (neut_glu_typ_pred i)
    with signature per_bot ==> eq ==> eq ==> iff as neut_glu_typ_pred_morphism_iff.
Proof with mautosolve.
  split; intros []; econstructor; intuition;
    match_by_head per_bot ltac:(fun H => specialize (H (length Δ)) as [? []]);
    functional_read_rewrite_clear; intuition.
Qed.

Add Parametric Morphism i : (neut_glu_typ_pred i)
    with signature per_bot ==> glu_typ_pred_equivalence as neut_glu_typ_pred_morphism_glu_typ_pred_equivalence.
Proof with mautosolve.
  split; apply neut_glu_typ_pred_morphism_iff; mauto.
Qed.

Add Parametric Morphism i : (neut_glu_exp_pred i)
    with signature per_bot ==> eq ==> eq ==> eq ==> eq ==> iff as neut_glu_exp_pred_morphism_iff.
Proof with mautosolve.
  split; intros []; econstructor; intuition;
    match_by_head per_bot ltac:(fun H => specialize (H (length Δ)) as [? []]);
    functional_read_rewrite_clear; intuition;
    match_by_head per_bot ltac:(fun H => rewrite H in *); eassumption.
Qed.

Add Parametric Morphism i : (neut_glu_exp_pred i)
    with signature per_bot ==> glu_exp_pred_equivalence as neut_glu_exp_pred_morphism_glu_exp_pred_equivalence.
Proof with mautosolve.
  split; apply neut_glu_exp_pred_morphism_iff; mauto.
Qed.

Morphism instances for pi_glu_*_preds

Add Parametric Morphism i IR : (pi_glu_typ_pred i IR)
    with signature glu_typ_pred_equivalence ==> glu_exp_pred_equivalence ==> eq ==> eq ==> eq ==> iff as pi_glu_typ_pred_morphism_iff.
Proof with mautosolve.
  split; intros []; econstructor; intuition.
Qed.

Add Parametric Morphism i IR : (pi_glu_typ_pred i IR)
    with signature glu_typ_pred_equivalence ==> glu_exp_pred_equivalence ==> eq ==> glu_typ_pred_equivalence as pi_glu_typ_pred_morphism_glu_typ_pred_equivalence.
Proof with mautosolve.
  split; intros []; econstructor; intuition.
Qed.

Add Parametric Morphism i IR : (pi_glu_exp_pred i IR)
    with signature glu_typ_pred_equivalence ==> glu_exp_pred_equivalence ==> relation_equivalence ==> eq ==> eq ==> eq ==> eq ==> eq ==> iff as pi_glu_exp_pred_morphism_iff.
Proof with mautosolve.
  split; intros []; econstructor; intuition.
Qed.

Add Parametric Morphism i IR : (pi_glu_exp_pred i IR)
    with signature glu_typ_pred_equivalence ==> glu_exp_pred_equivalence ==> relation_equivalence ==> eq ==> glu_exp_pred_equivalence as pi_glu_exp_pred_morphism_glu_exp_pred_equivalence.
Proof with mautosolve.
  split; intros []; econstructor; intuition.
Qed.

Lemma functional_glu_univ_elem : forall i a P P' El El',
    {{ DG a glu_univ_elem i P El }} ->
    {{ DG a glu_univ_elem i P' El' }} ->
    (P <∙> P') /\ (El <∙> El').
Proof.
  simpl.
  intros * Ha Ha'. gen P' El'.
  induction Ha using glu_univ_elem_ind; intros; basic_invert_glu_univ_elem Ha';
    apply_predicate_equivalence; try solve [split; reflexivity].
  assert ((IP <∙> IP0) /\ (IEl <∙> IEl0)) as [] by mauto.
  apply_predicate_equivalence.
  handle_per_univ_elem_irrel.
  (on_all_hyp: fun H => directed invert_per_univ_elem H).
  handle_per_univ_elem_irrel.
  split; [intros Γ C | intros Γ M C m].
  - split; intros []; econstructor; intuition;
      [rename equiv_m into equiv0_m; assert (equiv_m : in_rel m m) by intuition
      | assert (equiv0_m : in_rel0 m m) by intuition ];
      destruct_rel_mod_eval;
      functional_eval_rewrite_clear;
      assert ((OP m equiv_m <∙> OP0 m equiv0_m) /\ (OEl m equiv_m <∙> OEl0 m equiv0_m)) as [] by mauto 3;
      intuition.
  - split; intros []; econstructor; intuition;
      [rename equiv_n into equiv0_n; assert (equiv_n : in_rel n n) by intuition
      | assert (equiv0_n : in_rel0 n n) by intuition];
      destruct_rel_mod_eval;
      [assert (exists m0n, {{ $| m0 & n |↘ m0n }} /\ {{ Δ M0[σ] N : OT[σ,,N] ® m0n OEl n equiv_n }}) by intuition
      | assert (exists m0n, {{ $| m0 & n |↘ m0n }} /\ {{ Δ M0[σ] N : OT[σ,,N] ® m0n OEl0 n equiv0_n }}) by intuition];
      destruct_conjs;
      assert ((OP n equiv_n <∙> OP0 n equiv0_n) /\ (OEl n equiv_n <∙> OEl0 n equiv0_n)) as [] by mauto 3;
      eexists; split; intuition.
Qed.

Ltac apply_functional_glu_univ_elem1 :=
  let tactic_error o1 o2 := fail 2 "functional_glu_univ_elem biconditional between" o1 "and" o2 "cannot be solved" in
  match goal with
  | H1 : {{ DG ^?a glu_univ_elem ?i ?P1 ?El1 }},
      H2 : {{ DG ^?a glu_univ_elem ?i' ?P2 ?El2 }} |- _ =>
      unify i i';
      assert_fails (unify P1 P2; unify El1 El2);
      match goal with
      | H : P1 <∙> P2, H0 : El1 <∙> El2 |- _ => fail 1
      | H : P1 <∙> P2, H0 : El2 <∙> El1 |- _ => fail 1
      | H : P2 <∙> P1, H0 : El1 <∙> El2 |- _ => fail 1
      | H : P2 <∙> P1, H0 : El2 <∙> El1 |- _ => fail 1
      | _ => assert ((P1 <∙> P2) /\ (El1 <∙> El2)) as [] by (eapply functional_glu_univ_elem; [apply H1 | apply H2]) || tactic_error P1 P2
      end
  end.

Ltac apply_functional_glu_univ_elem :=
  repeat apply_functional_glu_univ_elem1.

Ltac handle_functional_glu_univ_elem :=
  functional_eval_rewrite_clear;
  fold glu_typ_pred in *;
  fold glu_exp_pred in *;
  apply_functional_glu_univ_elem;
  apply_predicate_equivalence;
  clear_dups.

Lemma glu_univ_elem_pi_clean_inversion1 : forall {i a ρ B in_rel P El},
  {{ DF a a per_univ_elem i in_rel }} ->
  {{ DG Π a ρ B glu_univ_elem i P El }} ->
  exists IP IEl (OP : forall c (equiv_c_c : {{ Dom c c in_rel }}), glu_typ_pred)
     (OEl : forall c (equiv_c_c : {{ Dom c c in_rel }}), glu_exp_pred) elem_rel,
      {{ DG a glu_univ_elem i IP IEl }} /\
        (forall c (equiv_c : {{ Dom c c in_rel }}) b,
            {{ B ρ c b }} ->
            {{ DG b glu_univ_elem i OP _ equiv_c OEl _ equiv_c }}) /\
        {{ DF Π a ρ B Π a ρ B per_univ_elem i elem_rel }} /\
        (P <∙> pi_glu_typ_pred i in_rel IP IEl OP) /\
        (El <∙> pi_glu_exp_pred i in_rel IP IEl elem_rel OEl).
Proof.
  intros *.
  simpl.
  intros Hinper Hglu.
  basic_invert_glu_univ_elem Hglu.
  handle_functional_glu_univ_elem.
  handle_per_univ_elem_irrel.
  do 5 eexists.
  repeat split.
  1,3: eassumption.
  1: instantiate (1 := fun c equiv_c Γ A M m => forall (b : domain) Pb Elb,
                          {{ B ρ c b }} ->
                          {{ DG b glu_univ_elem i Pb Elb }} ->
                          {{ Γ M : A ® m Elb }}).
  1: instantiate (1 := fun c equiv_c Γ A => forall (b : domain) Pb Elb,
                          {{ B ρ c b }} ->
                          {{ DG b glu_univ_elem i Pb Elb }} ->
                          {{ Γ A ® Pb }}).
  2-5: intros []; econstructor; mauto.
  all: intros.
  - assert {{ Dom c c in_rel0 }} as equiv0_c by intuition.
    assert {{ DG b glu_univ_elem i OP c equiv0_c OEl c equiv0_c }} by mauto 3.
    apply -> simple_glu_univ_elem_morphism_iff; [| reflexivity | |]; [eauto | |].
    + intros ? ? ? ?.
      split; intros; handle_functional_glu_univ_elem; intuition.
    + intros ? ?.
      split; [intros; handle_functional_glu_univ_elem |]; intuition.
  - assert {{ Dom m m in_rel0 }} as equiv0_m by intuition.
    assert {{ DG b glu_univ_elem i OP m equiv0_m OEl m equiv0_m }} by mauto 3.
    handle_functional_glu_univ_elem.
    intuition.
  - match_by_head per_univ_elem ltac:(fun H => directed invert_per_univ_elem H).
    destruct_rel_mod_eval.
    intuition.
  - assert {{ Dom n n in_rel0 }} as equiv0_n by intuition.
    assert (exists mn : domain, {{ $| m & n |↘ mn }} /\ {{ Δ M[σ] N : OT[σ,,N] ® mn OEl n equiv0_n }}) by mauto 3.
    destruct_conjs.
    eexists.
    intuition.
    assert {{ DG b glu_univ_elem i OP n equiv0_n OEl n equiv0_n }} by mauto 3.
    handle_functional_glu_univ_elem.
    intuition.
  - assert (exists mn : domain,
               {{ $| m & n |↘ mn }} /\
                 (forall (b : domain) (Pb : glu_typ_pred) (Elb : glu_exp_pred),
                     {{ B ρ n b }} ->
                     {{ DG b glu_univ_elem i Pb Elb }} ->
                     {{ Δ M[σ] N : OT[σ,,N] ® mn Elb }})) by intuition.
    destruct_conjs.
    match_by_head per_univ_elem ltac:(fun H => directed invert_per_univ_elem H).
    handle_per_univ_elem_irrel.
    destruct_rel_mod_eval.
    destruct_rel_mod_app.
    functional_eval_rewrite_clear.
    eexists.
    intuition.
Qed.

Lemma glu_univ_elem_pi_clean_inversion2 : forall {i a ρ B in_rel IP IEl P El},
  {{ DF a a per_univ_elem i in_rel }} ->
  {{ DG a glu_univ_elem i IP IEl }} ->
  {{ DG Π a ρ B glu_univ_elem i P El }} ->
  exists (OP : forall c (equiv_c_c : {{ Dom c c in_rel }}), glu_typ_pred)
     (OEl : forall c (equiv_c_c : {{ Dom c c in_rel }}), glu_exp_pred) elem_rel,
    (forall c (equiv_c : {{ Dom c c in_rel }}) b,
        {{ B ρ c b }} ->
        {{ DG b glu_univ_elem i OP _ equiv_c OEl _ equiv_c }}) /\
      {{ DF Π a ρ B Π a ρ B per_univ_elem i elem_rel }} /\
      (P <∙> pi_glu_typ_pred i in_rel IP IEl OP) /\
      (El <∙> pi_glu_exp_pred i in_rel IP IEl elem_rel OEl).
Proof.
  intros *.
  simpl.
  intros Hinper Hinglu Hglu.
  unshelve eapply (glu_univ_elem_pi_clean_inversion1 _) in Hglu; shelve_unifiable; [eassumption |];
    destruct Hglu as [? [? [? [? [? [? [? [? []]]]]]]]].
  handle_functional_glu_univ_elem.
  do 3 eexists.
  repeat split; try eassumption;
    intros []; econstructor; mauto.
Qed.

Ltac invert_glu_univ_elem H :=
  (unshelve eapply (glu_univ_elem_pi_clean_inversion2 _ _) in H; shelve_unifiable; [eassumption | eassumption |];
   destruct H as [? [? [? [? [? []]]]]])
  + (unshelve eapply (glu_univ_elem_pi_clean_inversion1 _) in H; shelve_unifiable; [eassumption |];
   destruct H as [? [? [? [? [? [? [? [? []]]]]]]]])
  + basic_invert_glu_univ_elem H.

Lemma glu_univ_elem_resp_per_univ : forall i a a' P El,
    {{ Dom a a' per_univ i }} ->
    {{ DG a glu_univ_elem i P El }} ->
    {{ DG a' glu_univ_elem i P El }}.
Proof.
  simpl.
  intros * [elem_rel Hper] Horig.
  pose proof Hper.
  gen P El.
  induction Hper using per_univ_elem_ind; intros; subst;
    saturate_refl_for per_univ_elem;
    invert_glu_univ_elem Horig; glu_univ_elem_econstructor; try eassumption; mauto;
    handle_per_univ_elem_irrel;
    handle_functional_glu_univ_elem.
  - intros.
    match_by_head per_univ_elem ltac:(fun H => directed invert_per_univ_elem H).
    destruct_rel_mod_eval.
    handle_per_univ_elem_irrel.
    intuition.
  - reflexivity.
  - apply neut_glu_typ_pred_morphism_glu_typ_pred_equivalence.
    eassumption.
  - apply neut_glu_exp_pred_morphism_glu_exp_pred_equivalence.
    eassumption.
Qed.

Morphism instances for glu_univ_elem

Add Parametric Morphism i : (glu_univ_elem i)
    with signature glu_typ_pred_equivalence ==> glu_exp_pred_equivalence ==> per_univ i ==> iff as glu_univ_elem_morphism_iff.
Proof with mautosolve.
  intros P P' HPP' El El' HElEl' a a' Haa'.
  rewrite HPP', HElEl'.
  split; intros; eapply glu_univ_elem_resp_per_univ; mauto.
  symmetry; eassumption.
Qed.

Add Parametric Morphism i R : (glu_univ_elem i)
    with signature glu_typ_pred_equivalence ==> glu_exp_pred_equivalence ==> per_univ_elem i R ==> iff as glu_univ_elem_morphism_iff'.
Proof with mautosolve.
  intros P P' HPP' El El' HElEl' **.
  rewrite HPP', HElEl'.
  split; intros; eapply glu_univ_elem_resp_per_univ; mauto.
  symmetry; mauto.
Qed.

Ltac saturate_glu_by_per1 :=
  match goal with
  | H : glu_univ_elem ?i ?P ?El ?a,
      H1 : per_univ_elem ?i _ ?a ?a' |- _ =>
      assert (glu_univ_elem i P El a') by (rewrite <- H1; eassumption);
      fail_if_dup
  | H : glu_univ_elem ?i ?P ?El ?a',
      H1 : per_univ_elem ?i _ ?a ?a' |- _ =>
      assert (glu_univ_elem i P El a) by (rewrite H1; eassumption);
      fail_if_dup
  end.

Ltac saturate_glu_by_per :=
  clear_dups;
  repeat saturate_glu_by_per1.

Lemma per_univ_glu_univ_elem : forall i a,
    {{ Dom a a per_univ i }} ->
    exists P El, {{ DG a glu_univ_elem i P El }}.
Proof.
  simpl.
  intros * [? Hper].
  induction Hper using per_univ_elem_ind; intros;
    try solve [do 2 eexists; unshelve (glu_univ_elem_econstructor; try reflexivity; subst; trivial)].

  - destruct_conjs.
    do 2 eexists.
    glu_univ_elem_econstructor; try (eassumption + reflexivity).
    + saturate_refl; eassumption.
    + instantiate (1 := fun (c : domain) (equiv_c : in_rel c c) Γ A M m =>
                          forall b P El,
                            {{ B' ρ' c b }} ->
                            glu_univ_elem i P El b ->
                            {{ Γ M : A ® m El }}).
      instantiate (1 := fun (c : domain) (equiv_c : in_rel c c) Γ A =>
                          forall b P El,
                            {{ B' ρ' c b }} ->
                            glu_univ_elem i P El b ->
                            {{ Γ A ® P }}).
      intros.
      (on_all_hyp: destruct_rel_by_assumption in_rel).
      handle_per_univ_elem_irrel.
      rewrite simple_glu_univ_elem_morphism_iff; try (eassumption + reflexivity);
        split; intros; handle_functional_glu_univ_elem; intuition.
    + enough {{ DF Π a ρ B Π a' ρ' B' per_univ_elem i elem_rel }} by (etransitivity; [symmetry |]; eassumption).
      per_univ_elem_econstructor; mauto.
      intros.
      (on_all_hyp: destruct_rel_by_assumption in_rel).
      econstructor; mauto.
  - do 2 eexists.
    glu_univ_elem_econstructor; try reflexivity; mauto.
Qed.

#[export]
Hint Resolve per_univ_glu_univ_elem : mcltt.

Corollary per_univ_elem_glu_univ_elem : forall i a R,
    {{ DF a a per_univ_elem i R }} ->
    exists P El, {{ DG a glu_univ_elem i P El }}.
Proof.
  intros.
  apply per_univ_glu_univ_elem; mauto.
Qed.

#[export]
Hint Resolve per_univ_elem_glu_univ_elem : mcltt.

Ltac saturate_glu_info1 :=
  match goal with
  | H : glu_univ_elem _ ?P _ _,
      H1 : ?P _ _ |- _ =>
      pose proof (glu_univ_elem_univ_lvl _ _ _ _ H _ _ H1);
      fail_if_dup
  | H : glu_univ_elem _ _ ?El _,
      H1 : ?El _ _ _ _ |- _ =>
      pose proof (glu_univ_elem_trm_escape _ _ _ _ H _ _ _ _ H1);
      fail_if_dup
  end.

Ltac saturate_glu_info :=
  clear_dups;
  repeat saturate_glu_info1.

#[local]
Hint Rewrite -> sub_decompose_q using solve [mauto 4] : mcltt.

Lemma glu_univ_elem_typ_monotone : forall i a P El,
    {{ DG a glu_univ_elem i P El }} ->
    forall Δ σ Γ A,
      {{ Γ A ® P }} ->
      {{ Δ w σ : Γ }} ->
      {{ Δ A[σ] ® P }}.
Proof.
  simpl. induction 1 using glu_univ_elem_ind; intros;
    saturate_weakening_escape;
    handle_functional_glu_univ_elem;
    simpl in *;
    try solve [bulky_rewrite].
  - simpl_glu_rel. econstructor; eauto; try solve [bulky_rewrite]; mauto 3.
    intros.
    saturate_weakening_escape.
    saturate_glu_info.
    invert_per_univ_elem H3.
    destruct_rel_mod_eval.
    simplify_evals.
    deepexec H1 ltac:(fun H => pose proof H).
    autorewrite with mcltt in *.
    mauto 3.

  - destruct_conjs.
    split; [mauto 3 |].
    intros.
    saturate_weakening_escape.
    autorewrite with mcltt.
    mauto 3.
Qed.

Lemma glu_univ_elem_exp_monotone : forall i a P El,
    {{ DG a glu_univ_elem i P El }} ->
    forall Δ σ Γ M A m,
      {{ Γ M : A ® m El }} ->
      {{ Δ w σ : Γ }} ->
      {{ Δ M[σ] : A[σ] ® m El }}.
Proof.
  simpl. induction 1 using glu_univ_elem_ind; intros;
    saturate_weakening_escape;
    handle_functional_glu_univ_elem;
    simpl in *;
    destruct_all.
  - repeat eexists; mauto 2; bulky_rewrite.
    eapply glu_univ_elem_typ_monotone; eauto.
  - repeat eexists; mauto 2; bulky_rewrite.

  - simpl_glu_rel.
    econstructor; mauto 4;
      intros;
      saturate_weakening_escape.
    + eapply glu_univ_elem_typ_monotone; eauto.
    + saturate_glu_info.
      invert_per_univ_elem H3.
      apply_equiv_left.
      destruct_rel_mod_eval.
      destruct_rel_mod_app.
      simplify_evals.
      deepexec H1 ltac:(fun H => pose proof H).
      autorewrite with mcltt in *.
      repeat eexists; eauto.
      assert {{ Δ0 s σ0,,N : Δ, IT[σ] }}.
      {
        econstructor; mauto 2.
        bulky_rewrite.
      }
      assert {{Δ0 M[σ][σ0] N M[σσ0] N : OT [σσ0,,N]}}.
      {
        rewrite <- @sub_eq_q_sigma_id_extend; mauto 4.
        rewrite <- @exp_eq_sub_compose_typ; mauto 3;
          [eapply wf_exp_eq_app_cong' |];
          mauto 4.
        symmetry.
        bulky_rewrite_in H4.
        assert {{ Δ0 Π IT[σσ0] (OT[q (σσ0)]) (Π IT OT)[σσ0] : Type@_ }} by mauto.
        eapply wf_exp_eq_conv'; mauto 4.
      }

      bulky_rewrite.
      edestruct H10 with (n := n) as [? []];
        simplify_evals; [| | eassumption];
        mauto.

  - simpl_glu_rel.
    econstructor; repeat split; mauto 3;
      intros;
      saturate_weakening_escape.
    + autorewrite with mcltt.
      mauto 3.
    + autorewrite with mcltt.
      etransitivity.
      * symmetry.
        eapply wf_exp_eq_sub_compose;
          mauto 3.
      * mauto 3.
Qed.

Add Parametric Morphism i a : (glu_elem_bot i a)
    with signature wf_ctx_eq ==> eq ==> eq ==> eq ==> iff as glu_elem_bot_morphism_iff1.
Proof.
  intros Γ Γ' HΓΓ' *.
  split; intros []; econstructor; mauto 4; [rewrite <- HΓΓ' | rewrite -> HΓΓ']; eassumption.
Qed.

Add Parametric Morphism i a Γ : (glu_elem_bot i a Γ)
    with signature wf_exp_eq Γ {{{ Type@i }}} ==> eq ==> eq ==> iff as glu_elem_bot_morphism_iff2.
Proof.
  intros A A' HAA' *.
  split; intros []; econstructor; mauto 3; [rewrite <- HAA' | | rewrite -> HAA' |];
    try eassumption;
    intros;
    assert {{ Δ A[σ] A'[σ] : Type@i }} as HAσA'σ by mauto 4;
    [rewrite <- HAσA'σ | rewrite -> HAσA'σ];
    mauto.
Qed.

Add Parametric Morphism i a Γ A : (glu_elem_bot i a Γ A)
    with signature wf_exp_eq Γ A ==> eq ==> iff as glu_elem_bot_morphism_iff3.
Proof.
  intros M M' HMM' *.
  split; intros []; econstructor; mauto 3; try (gen_presup HMM'; eassumption);
    intros;
    assert {{ Δ M[σ] M'[σ] : A[σ] }} as HMσM'σ by mauto 4;
    [rewrite <- HMσM'σ | rewrite -> HMσM'σ];
    mauto.
Qed.

Add Parametric Morphism i a : (glu_elem_top i a)
    with signature wf_ctx_eq ==> eq ==> eq ==> eq ==> iff as glu_elem_top_morphism_iff1.
Proof.
  intros Γ Γ' HΓΓ' *.
  split; intros []; econstructor; mauto 4; [rewrite <- HΓΓ' | rewrite -> HΓΓ']; eassumption.
Qed.

Add Parametric Morphism i a Γ : (glu_elem_top i a Γ)
    with signature wf_exp_eq Γ {{{ Type@i }}} ==> eq ==> eq ==> iff as glu_elem_top_morphism_iff2.
Proof.
  intros A A' HAA' *.
  split; intros []; econstructor; mauto 3; [rewrite <- HAA' | | rewrite -> HAA' |];
    try eassumption;
    intros;
    assert {{ Δ A[σ] A'[σ] : Type@i }} as HAσA'σ by mauto 4;
    [rewrite <- HAσA'σ | rewrite -> HAσA'σ];
    mauto.
Qed.

Add Parametric Morphism i a Γ A : (glu_elem_top i a Γ A)
    with signature wf_exp_eq Γ A ==> eq ==> iff as glu_elem_top_morphism_iff3.
Proof.
  intros M M' HMM' *.
  split; intros []; econstructor; mauto 3; try (gen_presup HMM'; eassumption);
    intros;
    assert {{ Δ M[σ] M'[σ] : A[σ] }} as HMσM'σ by mauto 4;
    [rewrite <- HMσM'σ | rewrite -> HMσM'σ];
    mauto.
Qed.

Add Parametric Morphism i a : (glu_typ_top i a)
    with signature wf_ctx_eq ==> eq ==> iff as glu_typ_top_morphism_iff1.
Proof.
  intros Γ Γ' HΓΓ' *.
  split; intros []; econstructor; mauto 4.
Qed.

Add Parametric Morphism i a Γ : (glu_typ_top i a Γ)
    with signature wf_exp_eq Γ {{{ Type@i }}} ==> iff as glu_typ_top_morphism_iff2.
Proof.
  intros A A' HAA' *.
  split; intros []; econstructor; mauto 3;
    try (gen_presup HAA'; eassumption);
    intros;
    assert {{ Δ A[σ] A'[σ] : Type@i }} as HAσA'σ by mauto 4;
    [rewrite <- HAσA'σ | rewrite -> HAσA'σ];
    mauto.
Qed.

Simple Morphism instance for glu_ctx_env

Add Parametric Morphism : glu_ctx_env
    with signature glu_sub_pred_equivalence ==> eq ==> iff as simple_glu_ctx_env_morphism_iff.
Proof.
  intros Sb Sb' HSbSb' a.
  split; intro Horig; [gen Sb' | gen Sb];
    induction Horig; econstructor;
    try (etransitivity; [symmetry + idtac|]; eassumption); eauto.
Qed.