m1-internship/FinitaryFirstOrderLogic.agda

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{-# OPTIONS --prop --rewriting #-}
open import PropUtil
module FinitaryFirstOrderLogic where
open import Agda.Primitive
open import ListUtil
variable
ℓ¹ ℓ² ℓ³ ℓ⁴ ℓ⁵ : Level
record FFOL : Set (lsuc (ℓ¹ ℓ² ℓ³ ℓ⁴ ℓ⁵)) where
infixr 10 _∘_
infixr 5 _⊢_
field
Con : Set ℓ¹
Sub : Con Con Set ℓ⁵ -- It makes a category
_∘_ : {Γ Δ Ξ : Con} Sub Δ Ξ Sub Γ Δ Sub Γ Ξ
∘-ass : {Γ Δ Ξ Ψ : Con}{α : Sub Γ Δ}{β : Sub Δ Ξ}{γ : Sub Ξ Ψ} (γ β) α γ (β α)
id : {Γ : Con} Sub Γ Γ
idl : {Γ Δ : Con} {σ : Sub Γ Δ} (id {Δ}) σ σ
idr : {Γ Δ : Con} {σ : Sub Γ Δ} σ (id {Γ}) σ
: Con -- The initial object of the category
ε : {Γ : Con} Sub Γ -- The morphism from the initial to any object
ε-u : {Γ : Con} {σ : Sub Γ } σ ε {Γ}
-- Functor Con → Set called Tm
Tm : Con Set ℓ²
_[_]t : {Γ Δ : Con} Tm Γ Sub Δ Γ Tm Δ -- The functor's action on morphisms
[]t-id : {Γ : Con} {x : Tm Γ} x [ id {Γ} ]t x
[]t-∘ : {Γ Δ Ξ : Con} {α : Sub Ξ Δ} {β : Sub Δ Γ} {t : Tm Γ} t [ β α ]t (t [ β ]t) [ α ]t
-- Tm : Set+
_▹ₜ : Con Con
πₜ¹ : {Γ Δ : Con} Sub Δ (Γ ▹ₜ) Sub Δ Γ
πₜ² : {Γ Δ : Con} Sub Δ (Γ ▹ₜ) Tm Δ
_,ₜ_ : {Γ Δ : Con} Sub Δ Γ Tm Δ Sub Δ (Γ ▹ₜ)
πₜ²∘,ₜ : {Γ Δ : Con} {σ : Sub Δ Γ} {t : Tm Δ} πₜ² (σ ,ₜ t) t
πₜ¹∘,ₜ : {Γ Δ : Con} {σ : Sub Δ Γ} {t : Tm Δ} πₜ¹ (σ ,ₜ t) σ
,ₜ∘πₜ : {Γ Δ : Con} {σ : Sub Δ (Γ ▹ₜ)} (πₜ¹ σ) ,ₜ (πₜ² σ) σ
,ₜ∘ : {Γ Δ Ξ : Con}{σ : Sub Γ Ξ}{δ : Sub Δ Γ}{t : Tm Γ} (σ ,ₜ t) δ (σ δ) ,ₜ (t [ δ ]t)
-- Functor Con → Set called For
For : Con Set ℓ³
_[_]f : {Γ Δ : Con} For Γ Sub Δ Γ For Δ -- The functor's action on morphisms
[]f-id : {Γ : Con} {F : For Γ} F [ id {Γ} ]f F
[]f-∘ : {Γ Δ Ξ : Con} {α : Sub Ξ Δ} {β : Sub Δ Γ} {F : For Γ} F [ β α ]f (F [ β ]f) [ α ]f
-- Formulas with relation on terms
R : {Γ : Con} (t u : Tm Γ) For Γ
R[] : {Γ Δ : Con} {σ : Sub Δ Γ} {t u : Tm Γ} (R t u) [ σ ]f R (t [ σ ]t) (u [ σ ]t)
-- Proofs
_⊢_ : (Γ : Con) For Γ Prop ℓ⁴
_[_]p : {Γ Δ : Con} {F : For Γ} Γ F (σ : Sub Δ Γ) Δ (F [ σ ]f) -- The functor's action on morphisms
-- Equalities below are useless because Γ ⊢ F is in prop
-- []p-id : {Γ : Con} → {F : For Γ} → {prf : Γ ⊢ F} → prf [ id {Γ} ]p ≡ prf
-- []p-∘ : {Γ Δ Ξ : Con} → {α : Sub Ξ Δ} → {β : Sub Δ Γ} → {F : For Γ} → {prf : Γ ⊢ F} → prf [ α ∘ β ]p ≡ (prf [ β ]p) [ α ]p
-- → Prop⁺
_▹ₚ_ : (Γ : Con) For Γ Con
πₚ¹ : {Γ Δ : Con} {F : For Γ} Sub Δ (Γ ▹ₚ F) Sub Δ Γ
πₚ² : {Γ Δ : Con} {F : For Γ} (σ : Sub Δ (Γ ▹ₚ F)) Δ (F [ πₚ¹ σ ]f)
_,ₚ_ : {Γ Δ : Con} {F : For Γ} (σ : Sub Δ Γ) Δ (F [ σ ]f) Sub Δ (Γ ▹ₚ F)
-- Equalities below are useless because Γ ⊢ F is in Prop
,ₚ∘πₚ : {Γ Δ : Con} {F : For Γ} {σ : Sub Δ (Γ ▹ₚ F)} (πₚ¹ σ) ,ₚ (πₚ² σ) σ
πₚ¹∘,ₚ : {Γ Δ : Con} {σ : Sub Δ Γ} {F : For Γ} {prf : Δ (F [ σ ]f)} πₚ¹ (σ ,ₚ prf) σ
-- πₚ²∘,ₚ : {Γ Δ : Con} → {σ : Sub Δ Γ} → {F : For Γ} → {prf : Δ ⊢ (F [ σ ]f)} → πₚ² (σ ,ₚ prf) ≡ prf
,ₚ∘ : {Γ Δ Ξ : Con}{σ : Sub Γ Ξ}{δ : Sub Δ Γ}{F : For Ξ}{prf : Γ (F [ σ ]f)} (σ ,ₚ prf) δ (σ δ) ,ₚ (substP (λ F Δ F) (≡sym []f-∘) (prf [ δ ]p))
-- Implication
_⇒_ : {Γ : Con} For Γ For Γ For Γ
[]f-⇒ : {Γ Δ : Con} {F G : For Γ} {σ : Sub Δ Γ} (F G) [ σ ]f (F [ σ ]f) (G [ σ ]f)
-- Forall
∀∀ : {Γ : Con} For (Γ ▹ₜ) For Γ
[]f-∀∀ : {Γ Δ : Con} {F : For (Γ ▹ₜ)} {σ : Sub Δ Γ} ( F) [ σ ]f ( (F [ (σ πₜ¹ id) ,ₜ πₜ² id ]f))
-- Lam & App
lam : {Γ : Con} {F : For Γ} {G : For Γ} (Γ ▹ₚ F) (G [ πₚ¹ id ]f) Γ (F G)
app : {Γ : Con} {F G : For Γ} Γ (F G) Γ F Γ G
-- Again, we don't write the _[_]p equalities as everything is in Prop
-- ∀i and ∀e
∀i : {Γ : Con} {F : For (Γ ▹ₜ)} (Γ ▹ₜ) F Γ ( F)
∀e : {Γ : Con} {F : For (Γ ▹ₜ)} Γ ( F) {t : Tm Γ} Γ ( F [(id {Γ}) ,ₜ t ]f)
-- Examples
-- Proof utils
forall-in : {Γ Δ : Con} {σ : Sub Γ Δ} {A : For (Δ ▹ₜ)} Γ (A [ (σ πₜ¹ id) ,ₜ πₜ² id ]f) Γ ( A [ σ ]f)
forall-in {Γ = Γ} f = substP (λ F Γ F) (≡sym ([]f-∀∀)) f
wkₜ : {Γ : Con} Sub (Γ ▹ₜ) Γ
wkₜ = πₜ¹ id
0ₜ : {Γ : Con} Tm (Γ ▹ₜ)
0 = πₜ² id
1ₜ : {Γ : Con} Tm (Γ ▹ₜ ▹ₜ)
1 = πₜ² (πₜ¹ id)
wkₚ : {Γ : Con} {A : For Γ} Sub (Γ ▹ₚ A) Γ
wkₚ = πₚ¹ id
0ₚ : {Γ : Con} {A : For Γ} Γ ▹ₚ A A [ πₚ¹ id ]f
0 = πₚ² id
-- Examples
ex0 : {A : For } (A A)
ex0 {A = A} = lam 0
{-
ex1 : {A : For (◇ ▹ₜ)} → ◇ ⊢ ((∀∀ A) ⇒ (∀∀ A))
-- πₚ¹ id is adding an unused variable (syntax's llift)
ex1 {A = A} = lam (forall-in (∀i (substP (λ σ → ((◇ ▹ₚ ∀∀ A) ▹ₜ) ⊢ (A [ σ ]f)) {!!} {!!})))
-- (∀ x ∀ y . A(y,x)) ⇒ ∀ x ∀ y . A(x,y)
-- translation is (∀ ∀ A(0,1)) => (∀ ∀ A(1,0))
ex1' : {A : For (◇ ▹ₜ ▹ₜ)} → ◇ ⊢ ((∀∀ (∀∀ A)) ⇒ ∀∀ (∀∀ ( A [ (ε ,ₜ 0ₜ) ,ₜ 1ₜ ]f)))
ex1' = {!!}
-- (A ⇒ ∀ x . B(x)) ⇒ ∀ x . A ⇒ B(x)
ex2 : {A : For ◇}{B : For (◇ ▹ₜ)} → ◇ ⊢ ((A ⇒ (∀∀ B)) ⇒ (∀∀ ((A [ wkₜ ]f) ⇒ B)))
ex2 = {!!}
-- ∀ x y . A(x,y) ⇒ ∀ x . A(x,x)
-- For simplicity, I swiched positions of parameters of A (somehow...)
ex3 : {A : For (◇ ▹ₜ ▹ₜ)} → ◇ ⊢ ((∀∀ (∀∀ A)) ⇒ (∀∀ (A [ id ,ₜ 0ₜ ]f)))
ex3 = {!!}
-- ∀ x . A (x) ⇒ ∀ x y . A(x)
ex4 : {A : For (◇ ▹ₜ)} → ◇ ⊢ ((∀∀ A) ⇒ (∀∀ (∀∀ (A [ ε ,ₜ 1ₜ ]f))))
ex4 = {!!}
-- (((∀ x . A (x)) ⇒ B)⇒ B) ⇒ ∀ x . ((A (x) ⇒ B) ⇒ B)
ex5 : {A : For (◇ ▹ₜ)}{B : For ◇} → ◇ ⊢ ((((∀∀ A) ⇒ B) ⇒ B) ⇒ (∀∀ ((A ⇒ (B [ wkₜ ]f)) ⇒ (B [ wkₜ ]f))))
ex5 = {!!}
-}
record Tarski : Set where
field
TM : Set
REL : TM TM Prop
infixr 10 _∘_
Con = Set
Sub : Con Con Set
Sub Γ Δ = (Γ Δ) -- It makes a posetal category
_∘_ : {Γ Δ Ξ : Con} Sub Δ Ξ Sub Γ Δ Sub Γ Ξ
f g = λ x f (g x)
id : {Γ : Con} Sub Γ Γ
id = λ x x
ε : {Γ : Con} Sub Γ ⊤ₛ -- The morphism from the initial to any object
ε Γ = ttₛ
ε-u : {Γ : Con} {σ : Sub Γ ⊤ₛ} σ ε {Γ}
ε-u = refl
-- Functor Con → Set called Tm
Tm : Con Set
Tm Γ = Γ TM
_[_]t : {Γ Δ : Con} Tm Γ Sub Δ Γ Tm Δ -- The functor's action on morphisms
t [ σ ]t = λ γ t (σ γ)
[]t-id : {Γ : Con} {x : Tm Γ} x [ id {Γ} ]t x
[]t-id = refl
[]t-∘ : {Γ Δ Ξ : Con} {α : Sub Ξ Δ} {β : Sub Δ Γ} {t : Tm Γ} t [ β α ]t (t [ β ]t) [ α ]t
[]t-∘ {α = α} {β} {t} = refl {_} {_} {λ z t (β (α z))}
_[_]tz : {Γ Δ : Con} {n : Nat} Array (Tm Γ) n Sub Δ Γ Array (Tm Δ) n
tz [ σ ]tz = map (λ s s [ σ ]t) tz
[]tz-∘ : {Γ Δ Ξ : Con} {α : Sub Ξ Δ} {β : Sub Δ Γ} {n : Nat} {tz : Array (Tm Γ) n} tz [ β α ]tz tz [ β ]tz [ α ]tz
[]tz-∘ {tz = zero} = refl
[]tz-∘ {α = α} {β = β} {tz = next x tz} = substP (λ tz' (next ((x [ β ]t) [ α ]t) tz') (((next x tz) [ β ]tz) [ α ]tz)) (≡sym ([]tz-∘ {α = α} {β = β} {tz = tz})) refl
[]tz-id : {Γ : Con} {n : Nat} {tz : Array (Tm Γ) n} tz [ id ]tz tz
[]tz-id {tz = zero} = refl
[]tz-id {tz = next x tz} = substP (λ tz' next x tz' next x tz) (≡sym ([]tz-id {tz = tz})) refl
thm : {Γ Δ : Con} {n : Nat} {tz : Array (Tm Γ) n} {σ : Sub Δ Γ} {δ : Δ} map (λ t t δ) (tz [ σ ]tz) map (λ t t (σ δ)) tz
thm {tz = zero} = refl
thm {tz = next x tz} {σ} {δ} = substP (λ tz' (next (x (σ δ)) (map (λ t t δ) (map (λ s γ s (σ γ)) tz))) (next (x (σ δ)) tz')) (thm {tz = tz}) refl
-- Tm⁺
_▹ₜ : Con Con
Γ ▹ₜ = Γ × TM
πₜ¹ : {Γ Δ : Con} Sub Δ (Γ ▹ₜ) Sub Δ Γ
πₜ¹ σ = λ x proj× (σ x)
πₜ² : {Γ Δ : Con} Sub Δ (Γ ▹ₜ) Tm Δ
πₜ² σ = λ x proj× (σ x)
_,ₜ_ : {Γ Δ : Con} Sub Δ Γ Tm Δ Sub Δ (Γ ▹ₜ)
σ ,ₜ t = λ x (σ x) ,× (t x)
πₜ²∘,ₜ : {Γ Δ : Con} {σ : Sub Δ Γ} {t : Tm Δ} πₜ² (σ ,ₜ t) t
πₜ²∘,ₜ {σ = σ} {t} = refl {a = t}
πₜ¹∘,ₜ : {Γ Δ : Con} {σ : Sub Δ Γ} {t : Tm Δ} πₜ¹ (σ ,ₜ t) σ
πₜ¹∘,ₜ = refl
,ₜ∘πₜ : {Γ Δ : Con} {σ : Sub Δ (Γ ▹ₜ)} (πₜ¹ σ) ,ₜ (πₜ² σ) σ
,ₜ∘πₜ = refl
,ₜ∘ : {Γ Δ Ξ : Con}{σ : Sub Γ Ξ}{δ : Sub Δ Γ}{t : Tm Γ} (σ ,ₜ t) δ (σ δ) ,ₜ (t [ δ ]t)
,ₜ∘ = refl
-- Functor Con → Set called For
For : Con Set
For Γ = Γ Prop
_[_]f : {Γ Δ : Con} For Γ Sub Δ Γ For Δ
F [ σ ]f = λ x F (σ x)
[]f-id : {Γ : Con} {F : For Γ} F [ id {Γ} ]f F
[]f-id = refl
[]f-∘ : {Γ Δ Ξ : Con} {α : Sub Ξ Δ} {β : Sub Δ Γ} {F : For Γ} F [ β α ]f (F [ β ]f) [ α ]f
[]f-∘ = refl
R : {Γ : Con} Tm Γ Tm Γ For Γ
R t u = λ γ REL (t γ) (u γ)
R[] : {Γ Δ : Con} {σ : Sub Δ Γ} {t u : Tm Γ} (R t u) [ σ ]f R (t [ σ ]t) (u [ σ ]t)
R[] {σ = σ} = cong₂ R refl refl
-- Proofs
_⊢_ : (Γ : Con) For Γ Prop
Γ F = (γ : Γ) F γ
_[_]p : {Γ Δ : Con} {F : For Γ} Γ F (σ : Sub Δ Γ) Δ (F [ σ ]f)
prf [ σ ]p = λ γ prf (σ γ)
-- Two rules are irrelevent beccause Γ ⊢ F is in Prop
-- → Prop⁺
_▹ₚ_ : (Γ : Con) For Γ Con
Γ ▹ₚ F = Γ ×'' F
πₚ¹ : {Γ Δ : Con} {F : For Γ} Sub Δ (Γ ▹ₚ F) Sub Δ Γ
πₚ¹ σ δ = proj×''₁ (σ δ)
πₚ² : {Γ Δ : Con} {F : For Γ} (σ : Sub Δ (Γ ▹ₚ F)) Δ (F [ πₚ¹ σ ]f)
πₚ² σ δ = proj×''₂ (σ δ)
_,ₚ_ : {Γ Δ : Con} {F : For Γ} (σ : Sub Δ Γ) Δ (F [ σ ]f) Sub Δ (Γ ▹ₚ F)
_,ₚ_ {F = F} σ pf δ = (σ δ) ,×'' pf δ
,ₚ∘πₚ : {Γ Δ : Con} {F : For Γ} {σ : Sub Δ (Γ ▹ₚ F)} (πₚ¹ σ) ,ₚ (πₚ² σ) σ
,ₚ∘πₚ = refl
πₚ¹∘,ₚ : {Γ Δ : Con} {σ : Sub Δ Γ} {F : For Γ} {prf : Δ (F [ σ ]f)} πₚ¹ {Γ} {Δ} {F} (σ ,ₚ prf) σ
πₚ¹∘,ₚ = refl
,ₚ∘ : {Γ Δ Ξ : Con}{σ : Sub Γ Ξ}{δ : Sub Δ Γ}{F : For Ξ}{prf : Γ (F [ σ ]f)}
(_,ₚ_ {F = F} σ prf) δ (σ δ) ,ₚ (substP (λ F Δ F) (≡sym ([]f-∘ {α = δ} {β = σ} {F = F})) (prf [ δ ]p))
,ₚ∘ {Γ} {Δ} {Ξ} {σ} {δ} {F} {prf} = refl
-- Implication
_⇒_ : {Γ : Con} For Γ For Γ For Γ
F G = λ γ (F γ) (G γ)
[]f-⇒ : {Γ Δ : Con} {F G : For Γ} {σ : Sub Δ Γ} (F G) [ σ ]f (F [ σ ]f) (G [ σ ]f)
[]f-⇒ = refl
-- Forall
∀∀ : {Γ : Con} For (Γ ▹ₜ) For Γ
{Γ} F = λ (γ : Γ) ( (t : TM) F (γ ,× t))
[]f-∀∀ : {Γ Δ : Con} {F : For (Γ ▹ₜ)} {σ : Sub Δ Γ} ( F) [ σ ]f ( (F [ (σ πₜ¹ id) ,ₜ πₜ² id ]f))
[]f-∀∀ {Γ} {Δ} {F} {σ} = refl
-- Lam & App
lam : {Γ : Con} {F : For Γ} {G : For Γ} (Γ ▹ₚ F) (G [ πₚ¹ id ]f) Γ (F G)
lam pf = λ γ x pf (γ ,×'' x)
app : {Γ : Con} {F G : For Γ} Γ (F G) Γ F Γ G
app pf pf' = λ γ pf γ (pf' γ)
-- Again, we don't write the _[_]p equalities as everything is in Prop
-- ∀i and ∀e
∀i : {Γ : Con} {F : For (Γ ▹ₜ)} (Γ ▹ₜ) F Γ ( F)
i p γ = λ t p (γ ,× t)
∀e : {Γ : Con} {F : For (Γ ▹ₜ)} Γ ( F) {t : Tm Γ} Γ ( F [(id {Γ}) ,ₜ t ]f)
e p {t} γ = p γ (t γ)
tod : FFOL
tod = record
{ Con = Con
; Sub = Sub
; _∘_ = _∘_
; ∘-ass = refl
; id = id
; idl = refl
; idr = refl
; = ⊤ₛ
; ε = ε
; ε-u = refl
; Tm = Tm
; _[_]t = _[_]t
; []t-id = []t-id
; []t-∘ = λ {Γ} {Δ} {Ξ} {α} {β} {t} []t-∘ {Γ} {Δ} {Ξ} {α} {β} {t}
; _▹ₜ = _▹ₜ
; πₜ¹ = πₜ¹
; πₜ² = πₜ²
; _,ₜ_ = _,ₜ_
; πₜ²∘,ₜ = λ {Γ} {Δ} {σ} πₜ²∘,ₜ {Γ} {Δ} {σ}
; πₜ¹∘,ₜ = λ {Γ} {Δ} {σ} {t} πₜ¹∘,ₜ {Γ} {Δ} {σ} {t}
; ,ₜ∘πₜ = ,ₜ∘πₜ
; ,ₜ∘ = λ {Γ} {Δ} {Ξ} {σ} {δ} {t} ,ₜ∘ {Γ} {Δ} {Ξ} {σ} {δ} {t}
; For = For
; _[_]f = _[_]f
; []f-id = []f-id
; []f-∘ = λ {Γ} {Δ} {Ξ} {α} {β} {F} []f-∘ {Γ} {Δ} {Ξ} {α} {β} {F}
; _⊢_ = _⊢_
; _[_]p = _[_]p
; _▹ₚ_ = _▹ₚ_
; πₚ¹ = πₚ¹
; πₚ² = πₚ²
; _,ₚ_ = _,ₚ_
; ,ₚ∘πₚ = ,ₚ∘πₚ
; πₚ¹∘,ₚ = λ {Γ} {Δ} {F} {σ} {p} πₚ¹∘,ₚ {Γ} {Δ} {F} {σ} {p}
; ,ₚ∘ = λ {Γ} {Δ} {Ξ} {σ} {δ} {F} {prf} ,ₚ∘ {Γ} {Δ} {Ξ} {σ} {δ} {F} {prf}
; _⇒_ = _⇒_
; []f-⇒ = λ {Γ} {F} {G} {σ} []f-⇒ {Γ} {F} {G} {σ}
; =
; []f-∀∀ = λ {Γ} {Δ} {F} {σ} []f-∀∀ {Γ} {Δ} {F} {σ}
; lam = lam
; app = app
; i = i
; e = e
; R = R
; R[] = λ {Γ} {Δ} {σ} {t} {u} R[] {Γ} {Δ} {σ} {t} {u}
}
-- (∀ x ∀ y . A(x,y)) ⇒ ∀ y ∀ x . A(y,x)
-- both sides are ∀ ∀ A (0,1)
ex1 : {A : For (⊤ₛ ▹ₜ ▹ₜ)} ⊤ₛ (( ( A)) ( ( A)))
ex1 _ hyp = hyp
-- (A ⇒ ∀ x . B(x)) ⇒ ∀ x . A ⇒ B(x)
ex2 : {A : For ⊤ₛ} {B : For (⊤ₛ ▹ₜ)} ⊤ₛ ((A ( B)) ( ((A [ πₜ¹ id ]f) B)))
ex2 _ h t h' = h h' t
-- ∀ x y . A(x,y) ⇒ ∀ x . A(x,x)
-- For simplicity, I swiched positions of parameters of A (somehow...)
ex3 : {A : For (⊤ₛ ▹ₜ ▹ₜ)} ⊤ₛ (( ( A)) ( (A [ id ,ₜ (πₜ² id) ]f)))
ex3 _ h t = h t t
-- ∀ x . A (x) ⇒ ∀ x y . A(x)
ex4 : {A : For (⊤ₛ ▹ₜ)} ⊤ₛ (( A) ( ( (A [ ε ,ₜ (πₜ² (πₜ¹ id)) ]f))))
ex4 {A} ◇◇ x t t' = x t
-- (((∀ x . A (x)) ⇒ B)⇒ B) ⇒ ∀ x . ((A (x) ⇒ B) ⇒ B)
ex5 : {A : For (⊤ₛ ▹ₜ)} {B : For ⊤ₛ} ⊤ₛ (((( A) B) B) ( ((A (B [ πₜ¹ id ]f)) (B [ πₜ¹ id ]f))))
ex5 ◇◇ h t h' = h (λ h'' h' (h'' t))
record Kripke : Set (lsuc (ℓ¹)) where
field
World : Set ℓ¹
_≤_ : World World Prop
≤refl : {w : World} w w
≤tran : {w w' w'' : World} w w' w' w'' w w'
TM : World Set ℓ¹
TM≤ : {w w' : World} w w' TM w TM w'
REL : (w : World) TM w TM w Prop ℓ¹
REL≤ : {w w' : World} {t u : TM w} (eq : w w') REL w t u REL w' (TM≤ eq t) (TM≤ eq u)
infixr 10 _∘_
Con = World Set ℓ¹
Sub : Con Con Set ℓ¹
Sub Δ Γ = (w : World) Δ w Γ w
_∘_ : {Γ Δ Ξ : Con} Sub Δ Ξ Sub Γ Δ Sub Γ Ξ
α β = λ w γ α w (β w γ)
id : {Γ : Con} Sub Γ Γ
id = λ w γ γ
: Con -- The initial object of the category
= λ w ⊤ₛ
ε : {Γ : Con} Sub Γ -- The morphism from the initial to any object
ε w Γ = ttₛ
-- Functor Con → Set called Tm
Tm : Con Set ℓ¹
Tm Γ = (w : World) (Γ w) TM w
_[_]t : {Γ Δ : Con} Tm Γ Sub Δ Γ Tm Δ -- The functor's action on morphisms
t [ σ ]t = λ w λ γ t w (σ w γ)
[]t-id : {Γ : Con} {x : Tm Γ} x [ id {Γ} ]t x
[]t-id = refl
[]t-∘ : {Γ Δ Ξ : Con} {α : Sub Ξ Δ} {β : Sub Δ Γ} {t : Tm Γ} t [ β α ]t (t [ β ]t) [ α ]t
[]t-∘ = refl
-- We simply define « bulk _[σ]t » (that acts on *n* terms from *Tm Γ*)
_[_]tz : {Γ Δ : Con} {n : Nat} Array (Tm Γ) n Sub Δ Γ Array (Tm Δ) n
tz [ σ ]tz = map (λ s s [ σ ]t) tz
[]tz-∘ : {Γ Δ Ξ : Con} {α : Sub Ξ Δ} {β : Sub Δ Γ} {n : Nat} {tz : Array (Tm Γ) n} tz [ β α ]tz tz [ β ]tz [ α ]tz
[]tz-∘ {tz = zero} = refl
[]tz-∘ {α = α} {β = β} {tz = next x tz} = substP (λ tz' (next ((x [ β ]t) [ α ]t) tz') (((next x tz) [ β ]tz) [ α ]tz)) (≡sym ([]tz-∘ {α = α} {β = β} {tz = tz})) refl
[]tz-id : {Γ : Con} {n : Nat} {tz : Array (Tm Γ) n} tz [ id ]tz tz
[]tz-id {tz = zero} = refl
[]tz-id {tz = next x tz} = substP (λ tz' next x tz' next x tz) (≡sym ([]tz-id {tz = tz})) refl
-- Tm⁺
_▹ₜ : Con Con
Γ ▹ₜ = λ w (Γ w) × (TM w)
πₜ¹ : {Γ Δ : Con} Sub Δ (Γ ▹ₜ) Sub Δ Γ
πₜ¹ σ = λ w λ x proj× (σ w x)
πₜ² : {Γ Δ : Con} Sub Δ (Γ ▹ₜ) Tm Δ
πₜ² σ = λ w λ x proj× (σ w x)
_,ₜ_ : {Γ Δ : Con} Sub Δ Γ Tm Δ Sub Δ (Γ ▹ₜ)
σ ,ₜ t = λ w λ x (σ w x) ,× (t w x)
πₜ²∘,ₜ : {Γ Δ : Con} {σ : Sub Δ Γ} {t : Tm Δ} πₜ² (σ ,ₜ t) t
πₜ²∘,ₜ {σ = σ} {t} = refl {a = t}
πₜ¹∘,ₜ : {Γ Δ : Con} {σ : Sub Δ Γ} {t : Tm Δ} πₜ¹ (σ ,ₜ t) σ
πₜ¹∘,ₜ = refl
,ₜ∘πₜ : {Γ Δ : Con} {σ : Sub Δ (Γ ▹ₜ)} (πₜ¹ σ) ,ₜ (πₜ² σ) σ
,ₜ∘πₜ = refl
,ₜ∘ : {Γ Δ Ξ : Con}{σ : Sub Γ Ξ}{δ : Sub Δ Γ}{t : Tm Γ} (σ ,ₜ t) δ (σ δ) ,ₜ (t [ δ ]t)
,ₜ∘ = refl
-- Functor Con → Set called For
For : Con Set (lsuc ℓ¹)
For Γ = (w : World) (Γ w) Prop ℓ¹
_[_]f : {Γ Δ : Con} For Γ Sub Δ Γ For Δ -- The functor's action on morphisms
F [ σ ]f = λ w λ x F w (σ w x)
[]f-id : {Γ : Con} {F : For Γ} F [ id {Γ} ]f F
[]f-id = refl
[]f-∘ : {Γ Δ Ξ : Con} {α : Sub Ξ Δ} {β : Sub Δ Γ} {F : For Γ} F [ β α ]f (F [ β ]f) [ α ]f
[]f-∘ = refl
-- Formulas with relation on terms
R : {Γ : Con} Tm Γ Tm Γ For Γ
R t u = λ w λ γ REL w (t w γ) (u w γ)
R[] : {Γ Δ : Con} {σ : Sub Δ Γ} {t u : Tm Γ} (R t u) [ σ ]f R (t [ σ ]t) (u [ σ ]t)
R[] {σ = σ} = cong₂ R refl refl
-- Proofs
_⊢_ : (Γ : Con) For Γ Prop ℓ¹
Γ F = w (γ : Γ w) F w γ
_[_]p : {Γ Δ : Con} {F : For Γ} Γ F (σ : Sub Δ Γ) Δ (F [ σ ]f) -- The functor's action on morphisms
prf [ σ ]p = λ w λ γ prf w (σ w γ)
-- Equalities below are useless because Γ ⊢ F is in prop
-- []p-id : {Γ : Con} → {F : For Γ} → {prf : Γ ⊢ F} → prf [ id {Γ} ]p ≡ prf
-- []p-∘ : {Γ Δ Ξ : Con} → {α : Sub Ξ Δ} → {β : Sub Δ Γ} → {F : For Γ} → {prf : Γ ⊢ F} → prf [ α ∘ β ]p ≡ (prf [ β ]p) [ α ]p
-- → Prop⁺
_▹ₚ_ : (Γ : Con) For Γ Con
Γ ▹ₚ F = λ w (Γ w) ×'' (F w)
πₚ¹ : {Γ Δ : Con} {F : For Γ} Sub Δ (Γ ▹ₚ F) Sub Δ Γ
πₚ¹ σ w δ = proj×''₁ (σ w δ)
πₚ² : {Γ Δ : Con} {F : For Γ} (σ : Sub Δ (Γ ▹ₚ F)) Δ (F [ πₚ¹ σ ]f)
πₚ² σ w δ = proj×''₂ (σ w δ)
_,ₚ_ : {Γ Δ : Con} {F : For Γ} (σ : Sub Δ Γ) Δ (F [ σ ]f) Sub Δ (Γ ▹ₚ F)
_,ₚ_ {F = F} σ pf w δ = (σ w δ) ,×'' pf w δ
,ₚ∘πₚ : {Γ Δ : Con} {F : For Γ} {σ : Sub Δ (Γ ▹ₚ F)} (πₚ¹ σ) ,ₚ (πₚ² σ) σ
,ₚ∘πₚ = refl
πₚ¹∘,ₚ : {Γ Δ : Con} {σ : Sub Δ Γ} {F : For Γ} {prf : Δ (F [ σ ]f)} πₚ¹ {Γ} {Δ} {F} (σ ,ₚ prf) σ
πₚ¹∘,ₚ = refl
,ₚ∘ : {Γ Δ Ξ : Con}{σ : Sub Γ Ξ}{δ : Sub Δ Γ}{F : For Ξ}{prf : Γ (F [ σ ]f)}
(_,ₚ_ {F = F} σ prf) δ (σ δ) ,ₚ (substP (λ F Δ F) (≡sym ([]f-∘ {α = δ} {β = σ} {F = F})) (prf [ δ ]p))
,ₚ∘ {Γ} {Δ} {Ξ} {σ} {δ} {F} {prf} = refl
-- Implication
_⇒_ : {Γ : Con} For Γ For Γ For Γ
F G = λ w λ γ ( w' w w' (F w γ) (G w γ))
[]f-⇒ : {Γ Δ : Con} {F G : For Γ} {σ : Sub Δ Γ} (F G) [ σ ]f (F [ σ ]f) (G [ σ ]f)
[]f-⇒ = refl
-- Forall
∀∀ : {Γ : Con} For (Γ ▹ₜ) For Γ
F = λ w λ γ t F w (γ ,× t)
[]f-∀∀ : {Γ Δ : Con} {F : For (Γ ▹ₜ)} {σ : Sub Δ Γ} ( F) [ σ ]f ( (F [ (σ πₜ¹ id) ,ₜ πₜ² id ]f))
[]f-∀∀ = refl
-- Lam & App
lam : {Γ : Con} {F : For Γ} {G : For Γ} (Γ ▹ₚ F) (G [ πₚ¹ id ]f) Γ (F G)
lam prf = λ w γ w' s h prf w (γ ,×'' h)
app : {Γ : Con} {F G : For Γ} Γ (F G) Γ F Γ G
app prf prf' = λ w γ prf w γ w ≤refl (prf' w γ)
-- Again, we don't write the _[_]p equalities as everything is in Prop
-- ∀i and ∀e
∀i : {Γ : Con} {F : For (Γ ▹ₜ)} (Γ ▹ₜ) F Γ ( F)
i p w γ = λ t p w (γ ,× t)
∀e : {Γ : Con} {F : For (Γ ▹ₜ)} Γ ( F) {t : Tm Γ} Γ ( F [(id {Γ}) ,ₜ t ]f)
e p {t} w γ = p w γ (t w γ)
tod : FFOL
tod = record
{ Con = Con
; Sub = Sub
; _∘_ = _∘_
; ∘-ass = refl
; id = id
; idl = refl
; idr = refl
; =
; ε = ε
; ε-u = refl
; Tm = Tm
; _[_]t = _[_]t
; []t-id = []t-id
; []t-∘ = λ {Γ} {Δ} {Ξ} {α} {β} {t} []t-∘ {Γ} {Δ} {Ξ} {α} {β} {t}
; _▹ₜ = _▹ₜ
; πₜ¹ = πₜ¹
; πₜ² = πₜ²
; _,ₜ_ = _,ₜ_
; πₜ²∘,ₜ = λ {Γ} {Δ} {σ} πₜ²∘,ₜ {Γ} {Δ} {σ}
; πₜ¹∘,ₜ = λ {Γ} {Δ} {σ} {t} πₜ¹∘,ₜ {Γ} {Δ} {σ} {t}
; ,ₜ∘πₜ = ,ₜ∘πₜ
; ,ₜ∘ = λ {Γ} {Δ} {Ξ} {σ} {δ} {t} ,ₜ∘ {Γ} {Δ} {Ξ} {σ} {δ} {t}
; For = For
; _[_]f = _[_]f
; []f-id = []f-id
; []f-∘ = λ {Γ} {Δ} {Ξ} {α} {β} {F} []f-∘ {Γ} {Δ} {Ξ} {α} {β} {F}
; _⊢_ = _⊢_
; _[_]p = _[_]p
; _▹ₚ_ = _▹ₚ_
; πₚ¹ = πₚ¹
; πₚ² = πₚ²
; _,ₚ_ = _,ₚ_
; ,ₚ∘πₚ = ,ₚ∘πₚ
; πₚ¹∘,ₚ = λ {Γ} {Δ} {F} {σ} {p} πₚ¹∘,ₚ {Γ} {Δ} {F} {σ} {p}
; ,ₚ∘ = λ {Γ} {Δ} {Ξ} {σ} {δ} {F} {prf} ,ₚ∘ {Γ} {Δ} {Ξ} {σ} {δ} {F} {prf}
; _⇒_ = _⇒_
; []f-⇒ = λ {Γ} {F} {G} {σ} []f-⇒ {Γ} {F} {G} {σ}
; =
; []f-∀∀ = λ {Γ} {Δ} {F} {σ} []f-∀∀ {Γ} {Δ} {F} {σ}
; lam = lam
; app = app
; i = i
; e = e
; R = R
; R[] = λ {Γ} {Δ} {σ} {t} {u} R[] {Γ} {Δ} {σ} {t} {u}
}
{-
-- Completeness proof
-- We first build our universal Kripke model
module ComplenessProof (M : FFOL {ℓ¹} {ℓ²} {ℓ³} {ℓ⁴} {ℓ⁵}) where
-- We have a model, we construct the Universal Kripke model of this model
World : Set ℓ¹
World = FFOL.Con M
_≤_ : World → World → Prop
Γ ≤ Δ = {!FFOL.Sub M Δ Γ!}
UK : Kripke
UK = record
{ World = World
; _≤_ = λ Δ Γ → {!FFOL.Sub M Δ Γ!}
; ≤refl = {!FFOL.id M!}
; ≤tran = {!FFOL.∘ M!}
; TM = {!!}
; TM≤ = {!!}
; REL = {!!}
; REL≤ = {!!}
}
-}