Update README.md

1 files changed, 1 insertions, 1 deletions

diff --git a/README.md b/README.md
index 757d1d0..79fe806 100644
--- a/README.md
+++ b/README.md
@@ -656,7 +656,7 @@ In interaction rules, attributes are recognised by a modifier `int` in order to
 
   ![dup_list](pic/dup_list.png)
   
-  We note that, in the first line from the top of the following execution example, there is a rule allowed to have not twice occurrences of *i* (here, it is three times, that is, once in left-hand side, and twice in the right-hand side). This is because the *i* is a variable for attributes.
+  We note that, in the first line from the top of the following execution example, there is a rule allowed to have not twice occurrences of *i* (here, it is three times, that is, once as `(int i):xs` in left-hand side, and twice as `(i:xs1)` and `(i:xs2)` in the right-hand side). This is because the *i* is a variable for attributes.
 
   ```
   >>> dup(a1,a2) >< (int i):xs => a1~(i:xs1), a2~(i:xs2), dup(xs1,xs2)~xs;