diff --git a/CppCoreGuidelines.md b/CppCoreGuidelines.md
index f55a9d1..2477e65 100644
--- a/CppCoreGuidelines.md
+++ b/CppCoreGuidelines.md
@@ -15304,7 +15304,7 @@ To use an object it must be in a valid state (defined formally or informally by
 
 ##### Note
 
-An [invariant](#Rc-struct) is logical condition for the members of an object that a constructor must establish for the public member functions to assume.
+An [invariant](#Rc-struct) is a logical condition for the members of an object that a constructor must establish for the public member functions to assume.
 
 ##### Enforcement