diff --git a/Visibility_2/doc/Visibility_2/Concepts/Visibility_2.h b/Visibility_2/doc/Visibility_2/Concepts/Visibility_2.h
index 4818bf63820..b4d970999ce 100644
--- a/Visibility_2/doc/Visibility_2/Concepts/Visibility_2.h
+++ b/Visibility_2/doc/Visibility_2/Concepts/Visibility_2.h
@@ -48,16 +48,16 @@ public:
   
   /*! 
     Tag identifying whether general polygons (with holes) are supported (either \ref CGAL::Tag_true or \ref CGAL::Tag_false). 
-    That is, the polygon is represented by a face \f$ f \f$ with no 
+    A general polygon is represented by a face \f$ f \f$ with no 
     isolated vertex and any edge of \f$ f \f$ separates \f$ f \f$ from another face.
     Note that this allows \f$ f \f$ to touch a vertex from several sides. 
   */
   typedef unspecified_type Supports_general_polygon_tag; 
 
   /*! 
-    Tag identifying whether general simple polygons are supported (either \ref CGAL::Tag_true or \ref CGAL::Tag_false). 
+    Tag identifying whether simple polygons are supported (either \ref CGAL::Tag_true or \ref CGAL::Tag_false). 
 
-    That is, the polygon is represented by a face \f$ f \f$ with no holes, 
+    A simple polygon is represented by a face \f$ f \f$ with no holes, 
     no isolated vertex and any edge of \f$ f \f$ separates \f$ f \f$ from another face.
     Note that this allows \f$ f \f$ to touch a vertex from several sides. 
   */