Fixed typo.

org.rodinp.handbook.feature/latex/reference-03.tex

@@ -274,7 +274,7 @@ The following reference subsections will have the form the form: \\[2em]
     A usual pattern for quantification is $\forall x_1\ldots,x_n~\qdot~\predp_1\limp \predp_2$ where
     $\predp_1$ is used to specify the types of the identifiers.
 
-    The existential quantification $\forall x_1\ldots,x_n~\qdot~\predp$ is true if a value of $x_1\ldots,x_n$ exists such that $\predp$ is satisfied.
+    The existential quantification $\exists x_1\ldots,x_n~\qdot~\predp$ is true if a value of $x_1\ldots,x_n$ exists such that $\predp$ is satisfied.
 
     The types of all identifiers $x_1\ldots,x_n$ must be inferable by $\predp$.
     They can be referenced in $\predp$.