diff --git a/algebra/cmra_big_op.v b/algebra/cmra_big_op.v
index 0fbf131eb3e9f9bfb9bb8bab2ccbf23a4f57cf49..42f06e44bb200f124bb90628c036c7b2f093ea75 100644
--- a/algebra/cmra_big_op.v
+++ b/algebra/cmra_big_op.v
@@ -10,7 +10,7 @@ Apart from that, we define the following big operators with binders build in:
   refers to each element at index [k].
 - The operator [ [⋅ map] k ↦ x ∈ m, P ] folds over a map [m]. The binder [x]
   refers to each element at index [k].
-- The operator [ [⋅ set] x ∈ X, P ] folds over a set [m]. The binder [x] refers
+- The operator [ [⋅ set] x ∈ X, P ] folds over a set [X]. The binder [x] refers
   to each element.
 
 Since these big operators are like quantifiers, they have the same precedence as