diff --git a/pyemma/coordinates/clustering/kmeans.py b/pyemma/coordinates/clustering/kmeans.py
index <HASH>..<HASH> 100644
--- a/pyemma/coordinates/clustering/kmeans.py
+++ b/pyemma/coordinates/clustering/kmeans.py
@@ -64,7 +64,7 @@ class KmeansClustering(AbstractClustering, ProgressReporter):
         tolerance : float
             stop iteration when the relative change in the cost function
 
-            ..1:                C(S) = \sum_{i=1}^{k} \sum_{\mathbf x \in S_i} \left\| \mathbf x - \boldsymbol\mu_i \right\|^2
+            .. math:: C(S) = \sum_{i=1}^{k} \sum_{\mathbf x \in S_i} \left\| \mathbf x - \boldsymbol\mu_i \right\|^2
 
             is smaller than tolerance.
         metric : str
[kmeans] fix math rendering of cost function (#<I>)