diff --git a/doc/src/Clustering/Clustering.do.txt b/doc/src/Clustering/Clustering.do.txt
index f9c0b9923..15c378d2a 100644
--- a/doc/src/Clustering/Clustering.do.txt
+++ b/doc/src/Clustering/Clustering.do.txt
@@ -106,7 +106,7 @@ description is a bit complicated and is lifted directly out of ESL HASTIE for
 deeper understanding purposes)
 
 o For a given cluster assignment $C$, and $k$ cluster means
-  $\{m_1, \cdots, m_k\}$. We minimize the total cluster variance with respect to
+  $\left{m_1, \cdots, m_k\right}$. We minimize the total cluster variance with respect to
   the cluster means $\{m_k\}$ yielding the means of the currently assigned
   clusters.
 o Given a current set of $k$ means $\{m_k\}$ the total cluster variance is