-- Authors: Floris van Doorn

import homotopy.smash ..move_to_lib .pushout homotopy.red_susp

open bool pointed eq equiv is_equiv sum bool prod unit circle cofiber prod.ops wedge is_trunc
     function red_susp unit

  /- To prove: Σ(X × Y) ≃ ΣX ∨ ΣY ∨ Σ(X ∧ Y) (?) (notation means suspension, wedge, smash) -/

  /- To prove: Σ(X ∧ Y) ≃ X ★ Y (?) (notation means suspension, smash, join) -/

  /- To prove: associative, A ∧ S¹ ≃ ΣA -/

variables {A B C D E F : Type*}

namespace smash

  section
  open pushout

  definition smash_functor' [unfold 7] (f : A →* C) (g : B →* D) : A ∧ B → C ∧ D :=
  begin
    fapply pushout.functor,
    { exact sum_functor f g },
    { exact prod_functor f g },
    { exact id },
    { intro v, induction v with a b,
      exact prod_eq idp (respect_pt g),
      exact prod_eq (respect_pt f) idp },
    { intro v, induction v with a b: reflexivity }
  end

  definition smash_functor [constructor] (f : A →* C) (g : B →* D) : A ∧ B →* C ∧ D :=
  begin
    fapply pmap.mk,
    { exact smash_functor' f g },
    { exact ap inl (prod_eq (respect_pt f) (respect_pt g)) },
  end

  definition functor_gluel (f : A →* C) (g : B →* D) (a : A) :
    ap (smash_functor f g) (gluel a) = ap (smash.mk (f a)) (respect_pt g) ⬝ gluel (f a) :=
  begin
    refine !pushout.elim_glue ⬝ _, esimp, apply whisker_right,
    induction D with D d₀, induction g with g g₀, esimp at *, induction g₀, reflexivity
  end

  definition functor_gluer (f : A →* C) (g : B →* D) (b : B) :
    ap (smash_functor f g) (gluer b) = ap (λc, smash.mk c (g b)) (respect_pt f) ⬝ gluer (g b) :=
  begin
    refine !pushout.elim_glue ⬝ _, esimp, apply whisker_right,
    induction C with C c₀, induction f with f f₀, esimp at *, induction f₀, reflexivity
  end

  definition functor_gluel' (f : A →* C) (g : B →* D) (a a' : A) :
    ap (smash_functor f g) (gluel' a a') = ap (smash.mk (f a)) (respect_pt g) ⬝
      gluel' (f a) (f a') ⬝ (ap (smash.mk (f a')) (respect_pt g))⁻¹ :=
  begin
    refine !ap_con ⬝ !functor_gluel ◾ (!ap_inv ⬝ !functor_gluel⁻²) ⬝ _,
    refine whisker_left _ !con_inv ⬝ _,
    refine !con.assoc⁻¹ ⬝ _, apply whisker_right,
    apply con.assoc
  end

  definition functor_gluer' (f : A →* C) (g : B →* D) (b b' : B) :
    ap (smash_functor f g) (gluer' b b') = ap (λc, smash.mk c (g b)) (respect_pt f) ⬝
      gluer' (g b) (g b') ⬝ (ap (λc, smash.mk c (g b')) (respect_pt f))⁻¹ :=
  begin
    refine !ap_con ⬝ whisker_left _ !ap_inv ⬝ _,
    refine !functor_gluer ◾  !functor_gluer⁻² ⬝ _,
    refine whisker_left _ !con_inv ⬝ _,
    refine !con.assoc⁻¹ ⬝ _, apply whisker_right,
    apply con.assoc
  end

  /- the statements of the above rules becomes easier if one of the functions respects the basepoint
     by reflexivity -/
  definition functor_gluel'2 {D : Type} (f : A →* C) (g : B → D) (a a' : A) :
    ap (smash_functor f (pmap_of_map g pt)) (gluel' a a') = gluel' (f a) (f a') :=
  begin
    refine !ap_con ⬝ whisker_left _ !ap_inv ⬝ _,
    refine (!functor_gluel ⬝ !idp_con) ◾  (!functor_gluel ⬝ !idp_con)⁻²
  end

  definition functor_gluer'2 {C : Type} (f : A → C) (g : B →* D) (b b' : B) :
    ap (smash_functor (pmap_of_map f pt) g) (gluer' b b') = gluer' (g b) (g b') :=
  begin
    refine !ap_con ⬝ whisker_left _ !ap_inv ⬝ _,
    refine (!functor_gluer ⬝ !idp_con) ◾  (!functor_gluer ⬝ !idp_con)⁻²
  end

  lemma functor_gluel'2_same {D : Type} (f : A →* C) (g : B → D) (a : A) :
    functor_gluel'2 f (pmap_of_map g pt) a a =
    ap02 (smash_functor f (pmap_of_map g pt)) (con.right_inv (gluel a)) ⬝
    (con.right_inv (gluel (f a)))⁻¹ :=
  begin
    refine _ ⬝ whisker_right _ (eq_top_of_square (!ap_con_right_inv_sq))⁻¹,
    refine _ ⬝ whisker_right _ !con_idp⁻¹,
    refine _ ⬝ !con.assoc⁻¹,
    apply whisker_left,
    apply eq_con_inv_of_con_eq, symmetry,
    apply con_right_inv_natural
  end

  lemma functor_gluer'2_same {C : Type} (f : A → C) (g : B →* D) (b : B) :
    functor_gluer'2 (pmap_of_map f pt) g b b =
    ap02 (smash_functor (pmap_of_map f pt) g) (con.right_inv (gluer b)) ⬝
    (con.right_inv (gluer (g b)))⁻¹ :=
  begin
    refine _ ⬝ whisker_right _ (eq_top_of_square (!ap_con_right_inv_sq))⁻¹,
    refine _ ⬝ whisker_right _ !con_idp⁻¹,
    refine _ ⬝ !con.assoc⁻¹,
    apply whisker_left,
    apply eq_con_inv_of_con_eq, symmetry,
    apply con_right_inv_natural
  end


  definition smash_functor_pcompose_homotopy (f' : C →* E) (f : A →* C) (g' : D →* F) (g : B →* D) :
    smash_functor (f' ∘* f) (g' ∘* g) ~ smash_functor f' g' ∘* smash_functor f g :=
  begin
    intro x, induction x with a b a b,
    { reflexivity },
    { reflexivity },
    { reflexivity },
    { apply eq_pathover, apply hdeg_square,
      refine !functor_gluel ⬝ _ ⬝ (ap_compose (smash_functor f' g') _ _)⁻¹,
      refine whisker_right _ !ap_con ⬝ !con.assoc ⬝ _ ⬝ ap02 _ !functor_gluel⁻¹,
      refine (!ap_compose'⁻¹ ⬝ !ap_compose') ◾ proof !functor_gluel⁻¹ qed ⬝ !ap_con⁻¹, },
    { apply eq_pathover, apply hdeg_square,
      refine !functor_gluer ⬝ _ ⬝ (ap_compose (smash_functor f' g') _ _)⁻¹,
      refine whisker_right _ !ap_con ⬝ !con.assoc ⬝ _ ⬝ ap02 _ !functor_gluer⁻¹,
      refine (!ap_compose'⁻¹ ⬝ !ap_compose') ◾ proof !functor_gluer⁻¹ qed ⬝ !ap_con⁻¹, }
  end

  definition smash_functor_pcompose [constructor] (f' : C →* E) (f : A →* C) (g' : D →* F) (g : B →* D) :
    smash_functor (f' ∘* f) (g' ∘* g) ~* smash_functor f' g' ∘* smash_functor f g :=
  begin
    fapply phomotopy.mk,
    { exact smash_functor_pcompose_homotopy f' f g' g },
    { exact abstract begin induction C, induction D, induction E, induction F,
      induction f with f f₀, induction f' with f' f'₀, induction g with g g₀, induction g' with g' g'₀,
      esimp at *, induction f₀, induction f'₀, induction g₀, induction g'₀, reflexivity end end }
  end

  definition smash_functor_phomotopy [constructor] {f f' : A →* C} {g g' : B →* D}
    (h₁ : f ~* f') (h₂ : g ~* g') : smash_functor f g ~* smash_functor f' g' :=
  begin
    induction h₁ using phomotopy_rec_on_idp,
    induction h₂ using phomotopy_rec_on_idp,
    reflexivity
    -- fapply phomotopy.mk,
    -- { intro x, induction x with a b a b,
    --   { exact ap011 smash.mk (h₁ a) (h₂ b) },
    --   { reflexivity },
    --   { reflexivity },
    --   { apply eq_pathover,
    --     refine !functor_gluel ⬝ph _ ⬝hp !functor_gluel⁻¹, exact sorry },
    --   { apply eq_pathover,
    --     refine !functor_gluer ⬝ph _ ⬝hp !functor_gluer⁻¹, exact sorry }},
    -- { esimp, }
  end

  definition smash_functor_phomotopy_refl [constructor] (f : A →* C) (g : B →* D) :
    smash_functor_phomotopy (phomotopy.refl f) (phomotopy.refl g) = phomotopy.rfl :=
  !phomotopy_rec_on_idp_refl ⬝ !phomotopy_rec_on_idp_refl

  definition smash_functor_pid [constructor] (A B : Type*) : smash_functor (pid A) (pid B) ~* pid (A ∧ B) :=
  begin
    fapply phomotopy.mk,
    { intro x, induction x with a b a b,
      { reflexivity },
      { reflexivity },
      { reflexivity },
      { apply eq_pathover_id_right, apply hdeg_square, exact !functor_gluel ⬝ !idp_con },
      { apply eq_pathover_id_right, apply hdeg_square, exact !functor_gluer ⬝ !idp_con }},
    { reflexivity }
  end

  definition smash_functor_pid_pcompose [constructor] (A : Type*) (g' : C →* D) (g : B →* C)
    : smash_functor (pid A) (g' ∘* g) ~* smash_functor (pid A) g' ∘* smash_functor (pid A) g :=
  smash_functor_phomotopy !pid_pcompose⁻¹* phomotopy.rfl ⬝* !smash_functor_pcompose

  definition smash_functor_pcompose_pid [constructor] (B : Type*) (f' : C →* D) (f : A →* C)
    : smash_functor (f' ∘* f) (pid B) ~* smash_functor f' (pid B) ∘* smash_functor f (pid B) :=
  smash_functor_phomotopy phomotopy.rfl !pid_pcompose⁻¹* ⬝* !smash_functor_pcompose

  definition smash_pequiv_smash [constructor] (f : A ≃* C) (g : B ≃* D) : A ∧ B ≃* C ∧ D :=
  begin
    fapply pequiv_of_pmap (smash_functor f g),
    apply pushout.is_equiv_functor,
    exact to_is_equiv (sum_equiv_sum f g)
  end

  end

  definition smash_pequiv_smash_left [constructor] (B : Type*) (f : A ≃* C) : A ∧ B ≃* C ∧ B :=
  smash_pequiv_smash f pequiv.rfl

  definition smash_pequiv_smash_right [constructor] (A : Type*) (g : B ≃* D) : A ∧ B ≃* A ∧ D :=
  smash_pequiv_smash pequiv.rfl g

  /- smash A B ≃ pcofiber (pprod_of_pwedge A B) -/

  definition elim_gluel' {P : Type} {Pmk : Πa b, P} {Pl Pr : P}
    (Pgl : Πa : A, Pmk a pt = Pl) (Pgr : Πb : B, Pmk pt b = Pr) (a a' : A) :
    ap (smash.elim Pmk Pl Pr Pgl Pgr) (gluel' a a') = Pgl a ⬝ (Pgl a')⁻¹ :=
  !ap_con ⬝ whisker_left _ !ap_inv ⬝ !elim_gluel ◾ !elim_gluel⁻²

  definition elim_gluer' {P : Type} {Pmk : Πa b, P} {Pl Pr : P}
    (Pgl : Πa : A, Pmk a pt = Pl) (Pgr : Πb : B, Pmk pt b = Pr) (b b' : B) :
    ap (smash.elim Pmk Pl Pr Pgl Pgr) (gluer' b b') = Pgr b ⬝ (Pgr b')⁻¹ :=
  !ap_con ⬝ whisker_left _ !ap_inv ⬝ !elim_gluer ◾ !elim_gluer⁻²

  definition elim_gluel'_same {P : Type} {Pmk : Πa b, P} {Pl Pr : P}
    (Pgl : Πa : A, Pmk a pt = Pl) (Pgr : Πb : B, Pmk pt b = Pr) (a : A) :
    elim_gluel' Pgl Pgr a a =
      ap02 (smash.elim Pmk Pl Pr Pgl Pgr) (con.right_inv (gluel a)) ⬝ (con.right_inv (Pgl a))⁻¹ :=
  begin
    refine _ ⬝ whisker_right _ (eq_top_of_square (!ap_con_right_inv_sq))⁻¹,
    refine _ ⬝ whisker_right _ !con_idp⁻¹,
    refine _ ⬝ !con.assoc⁻¹,
    apply whisker_left,
    apply eq_con_inv_of_con_eq, symmetry,
    apply con_right_inv_natural
  end

  definition elim_gluer'_same {P : Type} {Pmk : Πa b, P} {Pl Pr : P}
    (Pgl : Πa : A, Pmk a pt = Pl) (Pgr : Πb : B, Pmk pt b = Pr) (b : B) :
    elim_gluer' Pgl Pgr b b =
      ap02 (smash.elim Pmk Pl Pr Pgl Pgr) (con.right_inv (gluer b)) ⬝ (con.right_inv (Pgr b))⁻¹ :=
  begin
    refine _ ⬝ whisker_right _ (eq_top_of_square (!ap_con_right_inv_sq))⁻¹,
    refine _ ⬝ whisker_right _ !con_idp⁻¹,
    refine _ ⬝ !con.assoc⁻¹,
    apply whisker_left,
    apply eq_con_inv_of_con_eq, symmetry,
    apply con_right_inv_natural
  end

  definition elim'_gluel'_pt {P : Type} {Pmk : Πa b, P}
    (Pgl : Πa : A, Pmk a pt = Pmk pt pt) (Pgr : Πb : B, Pmk pt b = Pmk pt pt)
    (a : A) (ql : Pgl pt = idp) (qr : Pgr pt = idp) :
    ap (smash.elim' Pmk Pgl Pgr ql qr) (gluel' a pt) = Pgl a :=
  !elim_gluel' ⬝ whisker_left _ ql⁻²

  definition elim'_gluer'_pt {P : Type} {Pmk : Πa b, P}
    (Pgl : Πa : A, Pmk a pt = Pmk pt pt) (Pgr : Πb : B, Pmk pt b = Pmk pt pt)
    (b : B) (ql : Pgl pt = idp) (qr : Pgr pt = idp) :
    ap (smash.elim' Pmk Pgl Pgr ql qr) (gluer' b pt) = Pgr b :=
  !elim_gluer' ⬝ whisker_left _ qr⁻²

  definition prod_of_wedge [unfold 3] (v : pwedge A B) : A × B :=
  begin
    induction v with a b ,
    { exact (a, pt) },
    { exact (pt, b) },
    { reflexivity }
  end

  definition wedge_of_sum [unfold 3] (v : A + B) : pwedge A B :=
  begin
    induction v with a b,
    { exact pushout.inl a },
    { exact pushout.inr b }
  end


  definition prod_of_wedge_of_sum [unfold 3] (v : A + B) : prod_of_wedge (wedge_of_sum v) = prod_of_sum v :=
  begin
    induction v with a b,
    { reflexivity },
    { reflexivity }
  end

end smash open smash

namespace pushout

  definition eq_inl_pushout_wedge_of_sum [unfold 3] (v : pwedge A B) :
    inl pt = inl v :> pushout wedge_of_sum bool_of_sum :=
  begin
    induction v with a b,
    { exact glue (sum.inl pt) ⬝ (glue (sum.inl a))⁻¹, },
    { exact ap inl (glue ⋆) ⬝ glue (sum.inr pt) ⬝ (glue (sum.inr b))⁻¹, },
    { apply eq_pathover_constant_left,
      refine !con.right_inv ⬝pv _ ⬝vp !con_inv_cancel_right⁻¹, exact square_of_eq idp }
  end

  variables (A B)
  definition eq_inr_pushout_wedge_of_sum [unfold 3] (b : bool) :
    inl pt = inr b :> pushout (@wedge_of_sum A B) bool_of_sum :=
  begin
    induction b,
    { exact glue (sum.inl pt) },
    { exact ap inl (glue ⋆) ⬝ glue (sum.inr pt) }
  end

  definition is_contr_pushout_wedge_of_sum : is_contr (pushout (@wedge_of_sum A B) bool_of_sum) :=
  begin
    apply is_contr.mk (pushout.inl pt),
    intro x, induction x with v b w,
    { apply eq_inl_pushout_wedge_of_sum },
    { apply eq_inr_pushout_wedge_of_sum },
    { apply eq_pathover_constant_left_id_right,
      induction w with a b,
      { apply whisker_rt, exact vrfl },
      { apply whisker_rt, exact vrfl }}
  end

  definition bool_of_sum_of_bool {A B : Type*} (b : bool) : bool_of_sum (sum_of_bool A B b) = b :=
  by induction b: reflexivity

  /- a different proof, using pushout lemmas, and the fact that the wedge is the pushout of
     A + B <-- 2 --> 1 -/
  definition pushout_wedge_of_sum_equiv_unit : pushout (@wedge_of_sum A B) bool_of_sum ≃ unit :=
  begin
    refine pushout_hcompose_equiv (sum_of_bool A B) (wedge_equiv_pushout_sum A B ⬝e !pushout.symm)
             _ _ ⬝e _,
      exact erfl,
      intro x, induction x,
      reflexivity, reflexivity,
      exact bool_of_sum_of_bool,
    apply pushout_of_equiv_right
  end

end pushout open pushout

namespace smash

  variables (A B)

  definition smash_punit_pequiv [constructor] : smash A punit ≃* punit :=
  begin
    fapply pequiv_of_equiv,
    { fapply equiv.MK,
      { exact λx, ⋆ },
      { exact λx, pt },
      { intro x, induction x, reflexivity },
      { exact abstract begin intro x, induction x,
        { induction b, exact gluel' pt a },
        { exact gluel pt },
        { exact gluer pt },
        { apply eq_pathover_constant_left_id_right, apply square_of_eq_top,
          exact whisker_right _ !idp_con⁻¹ },
        { apply eq_pathover_constant_left_id_right, induction b,
          refine !con.right_inv ⬝pv _, exact square_of_eq idp } end end }},
    { reflexivity }
  end

  definition smash_equiv_cofiber : smash A B ≃ cofiber (@prod_of_wedge A B) :=
  begin
    unfold [smash, cofiber, smash'], symmetry,
    fapply pushout_vcompose_equiv wedge_of_sum,
    { symmetry, apply equiv_unit_of_is_contr, apply is_contr_pushout_wedge_of_sum },
    { intro x, reflexivity },
    { apply prod_of_wedge_of_sum }
  end

  definition pprod_of_pwedge [constructor] : pwedge A B →* A ×* B :=
  begin
    fconstructor,
    { exact prod_of_wedge },
    { reflexivity }
  end

  definition smash_pequiv_pcofiber [constructor] : smash A B ≃* pcofiber (pprod_of_pwedge A B) :=
  begin
    apply pequiv_of_equiv (smash_equiv_cofiber A B),
    exact cofiber.glue pt
  end

  variables {A B}

  /- commutativity -/

  definition smash_flip [unfold 3] (x : smash A B) : smash B A :=
  begin
    induction x,
    { exact smash.mk b a },
    { exact auxr },
    { exact auxl },
    { exact gluer a },
    { exact gluel b }
  end

  definition smash_flip_smash_flip [unfold 3] (x : smash A B) : smash_flip (smash_flip x) = x :=
  begin
    induction x,
    { reflexivity },
    { reflexivity },
    { reflexivity },
    { apply eq_pathover_id_right,
      refine ap_compose' smash_flip _ _ ⬝ ap02 _ !elim_gluel ⬝ !elim_gluer ⬝ph _,
      apply hrfl },
    { apply eq_pathover_id_right,
      refine ap_compose' smash_flip _ _ ⬝ ap02 _ !elim_gluer ⬝ !elim_gluel ⬝ph _,
      apply hrfl }
  end

  variables (A B)
  definition smash_comm [constructor] : smash A B ≃* smash B A :=
  begin
    fapply pequiv_of_equiv,
    { apply equiv.MK, do 2 exact smash_flip_smash_flip },
    { reflexivity }
  end
  variables {A B}

  /- smash A S¹ = red_susp A -/

  definition circle_elim_constant [unfold 5] {A : Type} {a : A} {p : a = a} (r : p = idp) (x : S¹) :
    circle.elim a p x = a :=
  begin
    induction x,
    { reflexivity },
    { apply eq_pathover_constant_right, apply hdeg_square, exact !elim_loop ⬝ r }
  end

  definition red_susp_of_smash_pcircle [unfold 2] (x : smash A S¹*) : red_susp A :=
  begin
    induction x using smash.elim,
    { induction b, exact base, exact equator a },
    { exact base },
    { exact base },
    { reflexivity },
    { exact circle_elim_constant equator_pt b }
  end

  definition smash_pcircle_of_red_susp [unfold 2] (x : red_susp A) : smash A S¹* :=
  begin
    induction x,
    { exact pt },
    { exact gluel' pt a ⬝ ap (smash.mk a) loop ⬝ gluel' a pt },
    { refine !con.right_inv ◾ _ ◾ !con.right_inv,
      exact ap_is_constant gluer loop ⬝ !con.right_inv }
  end
exit
  definition smash_pcircle_of_red_susp_of_smash_pcircle_pt [unfold 3] (a : A) (x : S¹*) :
    smash_pcircle_of_red_susp (red_susp_of_smash_pcircle (smash.mk a x)) = smash.mk a x :=
  begin
    induction x,
    { exact gluel' pt a },
    { exact abstract begin apply eq_pathover,
      refine ap_compose smash_pcircle_of_red_susp _ _ ⬝ph _,
      refine ap02 _ (elim_loop pt (equator a)) ⬝ !elim_equator ⬝ph _,
      -- make everything below this a lemma defined by path induction?
      refine !con_idp⁻¹ ⬝pv _, refine !con.assoc⁻¹ ⬝ph _, apply whisker_bl, apply whisker_lb,
      apply whisker_tl, apply hrfl end end }
  end

  definition concat2o [unfold 10] {A B : Type} {f g h : A → B} {q : f ~ g} {r : g ~ h} {a a' : A}
    {p : a = a'} (s : q a =[p] q a') (t : r a =[p] r a') : q a ⬝ r a =[p] q a' ⬝ r a' :=
  by induction p; exact idpo

  definition apd_con_fn [unfold 10] {A B : Type} {f g h : A → B} {q : f ~ g} {r : g ~ h} {a a' : A}
    (p : a = a') : apd (λa, q a ⬝ r a) p = concat2o (apd q p) (apd r p) :=
  by induction p; reflexivity

  -- definition apd_con_fn_constant [unfold 10] {A B : Type} {f : A → B} {b b' : B} {q : Πa, f a = b}
  --   {r : b = b'} {a a' : A} (p : a = a') :
  --   apd (λa, q a ⬝ r) p = concat2o (apd q p) (pathover_of_eq _ idp) :=
  -- by induction p; reflexivity

  theorem apd_constant' {A A' : Type} {B : A' → Type} {a₁ a₂ : A} {a' : A'} (b : B a')
    (p : a₁ = a₂) : apd (λx, b) p = pathover_of_eq p idp :=
  by induction p; reflexivity

  definition smash_pcircle_pequiv_red [constructor] (A : Type*) : smash A S¹* ≃* red_susp A :=
  begin
    fapply pequiv_of_equiv,
    { fapply equiv.MK,
      { exact red_susp_of_smash_pcircle },
      { exact smash_pcircle_of_red_susp },
      { exact abstract begin intro x, induction x,
        { reflexivity },
        { apply eq_pathover, apply hdeg_square,
          refine ap_compose red_susp_of_smash_pcircle _ _ ⬝ ap02 _ !elim_equator ⬝ _ ⬝ !ap_id⁻¹,
          refine !ap_con ⬝ (!ap_con ⬝ !elim_gluel' ◾ !ap_compose'⁻¹) ◾ !elim_gluel' ⬝ _,
          esimp, exact !idp_con ⬝ !elim_loop },
        { exact sorry } end end },
      { intro x, induction x,
        { exact smash_pcircle_of_red_susp_of_smash_pcircle_pt a b },
        { exact gluel pt },
        { exact gluer pt },
        { apply eq_pathover_id_right,
          refine ap_compose smash_pcircle_of_red_susp _ _ ⬝ph _,
          unfold [red_susp_of_smash_pcircle],
          refine ap02 _ !elim_gluel ⬝ph _,
          esimp, apply whisker_rt, exact vrfl },
        { apply eq_pathover_id_right,
          refine ap_compose smash_pcircle_of_red_susp _ _ ⬝ph _,
          unfold [red_susp_of_smash_pcircle],
          -- not sure why so many implicit arguments are needed here...
          refine ap02 _ (@smash.elim_gluer A S¹* _ (λa, circle.elim red_susp.base (equator a)) red_susp.base red_susp.base (λa, refl red_susp.base) (circle_elim_constant equator_pt) b) ⬝ph _,
          apply square_of_eq, induction b,
          { exact whisker_right _ !con.right_inv },
          { apply eq_pathover_dep, refine !apd_con_fn ⬝pho _ ⬝hop !apd_con_fn⁻¹,
            refine ap (λx, concat2o x _) !rec_loop ⬝pho _ ⬝hop (ap011 concat2o (apd_compose1 (λa b, ap smash_pcircle_of_red_susp b) (circle_elim_constant equator_pt) loop) !apd_constant')⁻¹,
            exact sorry }

          }}},
    { reflexivity }
  end

  /- smash A S¹ = susp A -/
  open susp


  definition psusp_of_smash_pcircle [unfold 2] (x : smash A S¹*) : psusp A :=
  begin
    induction x using smash.elim,
    { induction b, exact pt, exact merid a ⬝ (merid pt)⁻¹ },
    { exact pt },
    { exact pt },
    { reflexivity },
    { induction b, reflexivity, apply eq_pathover_constant_right, apply hdeg_square,
      exact !elim_loop ⬝ !con.right_inv }
  end

  definition smash_pcircle_of_psusp [unfold 2] (x : psusp A) : smash A S¹* :=
  begin
    induction x,
    { exact pt },
    { exact pt },
    { exact gluel' pt a ⬝ (ap (smash.mk a) loop ⬝ gluel' a pt) },
  end

 -- the definitions below compile, but take a long time to do so and have sorry's in them
  definition smash_pcircle_of_psusp_of_smash_pcircle_pt [unfold 3] (a : A) (x : S¹*) :
    smash_pcircle_of_psusp (psusp_of_smash_pcircle (smash.mk a x)) = smash.mk a x :=
  begin
    induction x,
    { exact gluel' pt a },
    { exact abstract begin apply eq_pathover,
      refine ap_compose smash_pcircle_of_psusp _ _ ⬝ph _,
      refine ap02 _ (elim_loop north (merid a ⬝ (merid pt)⁻¹)) ⬝ph _,
      refine !ap_con ⬝ (!elim_merid ◾ (!ap_inv ⬝ !elim_merid⁻²)) ⬝ph _,
      -- make everything below this a lemma defined by path induction?
      exact sorry,
      -- refine !con_idp⁻¹ ⬝pv _, apply whisker_tl, refine !con.assoc⁻¹ ⬝ph _,
      -- apply whisker_bl, apply whisker_lb,
      -- refine !con_idp⁻¹ ⬝pv _, apply whisker_tl, apply hrfl
      -- refine !con_idp⁻¹ ⬝pv _, apply whisker_tl,
      -- refine !con.assoc⁻¹ ⬝ph _, apply whisker_bl, apply whisker_lb, apply hrfl
      -- apply square_of_eq, rewrite [+con.assoc], apply whisker_left, apply whisker_left,
      -- symmetry, apply con_eq_of_eq_inv_con, esimp, apply con_eq_of_eq_con_inv,
      -- refine _⁻² ⬝ !con_inv, refine _ ⬝ !con.assoc,
      -- refine _ ⬝ whisker_right _ !inv_con_cancel_right⁻¹, refine _ ⬝ !con.right_inv⁻¹,
      -- refine !con.right_inv ◾ _, refine _ ◾ !con.right_inv,
      -- refine !ap_mk_right ⬝ !con.right_inv
      end end }
  end

  -- definition smash_pcircle_of_psusp_of_smash_pcircle_gluer_base (b : S¹*)
  --   : square (smash_pcircle_of_psusp_of_smash_pcircle_pt (Point A) b)
  --            (gluer pt)
  --            (ap smash_pcircle_of_psusp (ap (λ a, psusp_of_smash_pcircle a) (gluer b)))
  --            (gluer b) :=
  -- begin
  --   refine ap02 _ !elim_gluer ⬝ph _,
  --   induction b,
  --   { apply square_of_eq, exact whisker_right _ !con.right_inv },
  --   { apply square_pathover', exact sorry }
  -- end

exit
  definition smash_pcircle_pequiv [constructor] (A : Type*) : smash A S¹* ≃* psusp A :=
  begin
    fapply pequiv_of_equiv,
    { fapply equiv.MK,
      { exact psusp_of_smash_pcircle },
      { exact smash_pcircle_of_psusp },
      { exact abstract begin intro x, induction x,
        { reflexivity },
        { exact merid pt },
        { apply eq_pathover_id_right,
          refine ap_compose psusp_of_smash_pcircle _ _ ⬝ph _,
          refine ap02 _ !elim_merid ⬝ph _,
          rewrite [↑gluel', +ap_con, +ap_inv, -ap_compose'],
          refine (_ ◾ _⁻² ◾ _ ◾ (_ ◾ _⁻²)) ⬝ph _,
          rotate 5, do 2 (unfold [psusp_of_smash_pcircle]; apply elim_gluel),
          esimp, apply elim_loop, do 2 (unfold [psusp_of_smash_pcircle]; apply elim_gluel),
          refine idp_con (merid a ⬝ (merid (Point A))⁻¹) ⬝ph _,
          apply square_of_eq, refine !idp_con ⬝ _⁻¹, apply inv_con_cancel_right } end end },
      { intro x, induction x using smash.rec,
        { exact smash_pcircle_of_psusp_of_smash_pcircle_pt a b },
        { exact gluel pt },
        { exact gluer pt },
        { apply eq_pathover_id_right,
          refine ap_compose smash_pcircle_of_psusp _ _ ⬝ph _,
          unfold [psusp_of_smash_pcircle],
          refine ap02 _ !elim_gluel ⬝ph _,
          esimp, apply whisker_rt, exact vrfl },
        { apply eq_pathover_id_right,
          refine ap_compose smash_pcircle_of_psusp _ _ ⬝ph _,
          unfold [psusp_of_smash_pcircle],
          refine ap02 _ !elim_gluer ⬝ph _,
          induction b,
          { apply square_of_eq, exact whisker_right _ !con.right_inv },
          { exact sorry}
          }}},
    { reflexivity }
  end

end smash