Remove unused code from Utils

Signed-off-by: Danila Fedorin <danila.fedorin@gmail.com>

Language/Graphs.agda

@@ -15,7 +15,7 @@ open import Data.Vec.Properties using (cast-is-id; ++-assoc; lookup-++ˡ; cast-s
 open import Relation.Binary.PropositionalEquality as Eq using (_≡_; sym; refl; subst; trans)
 
 open import Lattice
-open import Utils using (x∈xs⇒fx∈fxs; _⊗_; _,_; ∈-cartesianProduct)
+open import Utils using (x∈xs⇒fx∈fxs; ∈-cartesianProduct)
 
 record Graph : Set where
     constructor MkGraph

Utils.agda

@@ -71,16 +71,6 @@ data Pairwise {a} {b} {c} {A : Set a} {B : Set b} (P : A → B → Set c) : List
           P x y → Pairwise P xs ys →
           Pairwise P (x ∷ xs) (y ∷ ys)
 
-infixr 2 _⊗_
-data _⊗_ {a p q} {A : Set a} (P : A → Set p) (Q : A → Set q) : A → Set (a ⊔ℓ p ⊔ℓ q) where
-    _,_ : ∀ {val : A} → P val → Q val → (P ⊗ Q) val
-
-proj₁ : ∀ {a p q} {A : Set a} {P : A → Set p} {Q : A → Set q} {a : A} → (P ⊗ Q) a → P a
-proj₁ (v , _) = v
-
-proj₂ : ∀ {a p q} {A : Set a} {P : A → Set p} {Q : A → Set q} {a : A} → (P ⊗ Q) a → Q a
-proj₂ (_ , v) = v
-
 ∈-cartesianProduct : ∀ {a b} {A : Set a} {B : Set b}
                      {x : A} {xs : List A} {y : B} {ys : List B} →
                      x ∈ xs → y ∈ ys → (x Prod., y) ∈ cartesianProduct xs ys