diff --git a/README.md b/README.md
index 66ce9f1..ee48d51 100644
--- a/README.md
+++ b/README.md
@@ -71,8 +71,7 @@ The topics covered in this script will be:
    12.1 Linear Operators  
    12.2 Dual Spaces  
    12.3 Hilbert Spaces  
-   12.4 Orthonormal Sets  
-   12.5 Adjoint Operators
+   12.4 Adjoint Operators
 
 13. Spectral Theory  
    13.1 Spectral Theory of Bounded Linear Operators