diff --git a/README.md b/README.md
index 33d3e12..6581d11 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ expressions:
 
 $$
 \mathbf{Y} = \mathbb{KLT}\{\mathbf{X}\}, \\
-C = \frac{1}{n-1}\mathbf{X}*\mathbf{X}, \\
+\mathbf{C} = \frac{1}{n-1}\mathbf{X}*\mathbf{X}, \\
 \mathbf{V}^{-1}\mathbf{C}\mathbf{V} = \mathbf{D}, \\
 \mathit{W} \subset \mathit{V}, \\
 \mathbf{T} = \mathbf{B} \cdot \mathbf{W}.