diff --git a/info/exercises/src/ex-04/ex/grammar.tex b/info/exercises/src/ex-04/ex/grammar.tex
index 9fe75195547790eb2ee8736fc04101d4f62e9776..3147792a061a10247c5f8990ea53cf971865b1eb 100644
--- a/info/exercises/src/ex-04/ex/grammar.tex
+++ b/info/exercises/src/ex-04/ex/grammar.tex
@@ -251,7 +251,7 @@
         
       \end{enumerate}
       \item Argument similar to Exercise Set 2 Problem 4 (same pair of
-      grammars). \(B_1 \subset B_2\) as relations can be seen by producing a
+      grammars). \(B_1 \subseteq B_2\) as relations can be seen by producing a
       derivation tree for each possible case in \(B_1\). For the other
       direction, \(B_2 \subseteq B_1\), it is first convenient to prove
       that \(B_1\) is closed under concatenation, i.e., if \(w_1, w_2 \in B_1\)