diff --git a/background.tex b/background.tex
index 8d30cff35a2d24d573665e93af991a57d4ad0d07..9550b00cebc11e114d034d141af6eda4f17f0544 100644
--- a/background.tex
+++ b/background.tex
@@ -199,8 +199,7 @@
   and defines \des{morphism} as arbitrary
   \(\Hom{\Rel}{X}{Y} \subseteq X \times Y\).
 
-  \(\Rel\) is \emph{self-dual}, since \(\op{\Rel}\) is the same as
-  \(\Rel\).
+  \(\Rel\) is \emph{self-dual}, since \(\op{\Rel} \cong \Rel\).
 \end{example}
 
 \begin{example}\label{ex:par}