diff --git a/lib-nested-core/src/utils/bimap.rs b/lib-nested-core/src/utils/bimap.rs
deleted file mode 100644
index 8bd41b6..0000000
--- a/lib-nested-core/src/utils/bimap.rs
+++ /dev/null
@@ -1,24 +0,0 @@
-use std::{collections::HashMap, hash::Hash};
-
-//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
-
-pub struct Bimap<V: Eq + Hash, Λ: Eq + Hash> {
-    pub mλ: HashMap<V, Λ>,
-    pub my: HashMap<Λ, V>,
-}
-
-impl<V: Eq + Hash + Clone, Λ: Eq + Hash + Clone> Bimap<V, Λ> {
-    pub fn new() -> Self {
-        Bimap {
-            mλ: HashMap::new(),
-            my: HashMap::new(),
-        }
-    }
-
-    pub fn insert(&mut self, y: V, λ: Λ) {
-        self.mλ.insert(y.clone(), λ.clone());
-        self.my.insert(λ, y);
-    }
-}
-
-//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
diff --git a/lib-nested-core/src/utils/mod.rs b/lib-nested-core/src/utils/mod.rs
index 8e8f5dd..f97b6e5 100644
--- a/lib-nested-core/src/utils/mod.rs
+++ b/lib-nested-core/src/utils/mod.rs
@@ -1,5 +1,2 @@
-pub mod bimap;
 pub mod modulo;
-
 pub use modulo::modulo;
-pub use bimap::Bimap;