diff --git a/xy.h b/xy.h
index 2d734e8..6a742ce 100644
--- a/xy.h
+++ b/xy.h
@@ -6,7 +6,7 @@
 *
 * xy:
 *
-*   Xiangyang or Xianyang or something else
+*   y = f(x)
 * -------------------------------------------------------------*/
 
 #ifndef XY_H