Clean up imports a bit

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

Lattice.agda

@@ -3,20 +3,13 @@ module Lattice where
 open import Equivalence
 import Chain
 
-import Data.Nat.Properties as NatProps
-open import Relation.Binary.PropositionalEquality as Eq using (_≡_; sym; subst)
-open Eq.≡-Reasoning using (begin_; _≡⟨⟩_; step-≡; _∎)
 open import Relation.Binary.Core using (_Preserves_⟶_ )
-open import Relation.Nullary using (Dec; ¬_; yes; no)
-open import Data.Nat as Nat using (ℕ; _≤_; _+_; suc)
-open import Data.Product using (_×_; Σ; _,_; proj₁; proj₂)
+open import Relation.Nullary using (Dec; ¬_)
+open import Data.Nat as Nat using (ℕ)
+open import Data.Product using (_×_; Σ; _,_)
 open import Data.Sum using (_⊎_; inj₁; inj₂)
 open import Agda.Primitive using (lsuc; Level) renaming (_⊔_ to _⊔ℓ_)
 open import Function.Definitions using (Injective)
-open import Data.Empty using (⊥)
-
-absurd : ∀ {a} {A : Set a} →  ⊥ → A
-absurd ()
 
 IsDecidable : ∀ {a} {A : Set a} (R : A → A → Set a) → Set a
 IsDecidable {a} {A} R = ∀ (a₁ a₂ : A) → Dec (R a₁ a₂)