diff --git a/prerequisites.tex b/prerequisites.tex
index d309d29..beafa93 100644
--- a/prerequisites.tex
+++ b/prerequisites.tex
@@ -47,7 +47,7 @@
 				                       & \rotmat{2 \pi s_2 / q} &        &                        \\
 				                       &                        & \ddots &                        \\
 				                       &                        &        & \rotmat{2 \pi s_n / q}
-			\end{pmatrix}
+			\end{pmatrix}.
 		\end{align*}
 	\end{definition}