diff --git a/chapters/arrays.tex b/chapters/arrays.tex
index d5d19943d..65b39442e 100644
--- a/chapters/arrays.tex
+++ b/chapters/arrays.tex
@@ -1378,7 +1378,7 @@ \subsection{Scalar Exponentiation of Matrices}\label{scalar-exponentiation-of-sq
 
 \subsection{Slice Operation}\label{slice-operation}
 
-The following holds for slice operations:
+The following holds for slice\index{slice} operations:
 \begin{itemize}
 \item
   If the component reference \lstinline!a! is an array containing scalar components and \lstinline!m! is a component of those components, the component reference \lstinline!a.m! is interpreted as a slice operation.
diff --git a/chapters/operatorsandexpressions.tex b/chapters/operatorsandexpressions.tex
index b5dce3440..cfe99d7b5 100644
--- a/chapters/operatorsandexpressions.tex
+++ b/chapters/operatorsandexpressions.tex
@@ -1555,6 +1555,10 @@ \section{Variability of Expressions}\label{variability-of-expressions}
   When determining whether an equation can contribute to solving for a variable \lstinline!v! (for instance, when applying the perfect matching rule, see \cref{synchronous-data-flow-principle-and-single-assignment-rule}), the equation can only be considered contributing if the resulting solution would be at most as variable as \lstinline!v!.
 \end{itemize}
 
+The variability of \lstinline!a[I].x! is the highest variability of \lstinline!I! and \lstinline!x!.
+Note that the variability of \lstinline!x! takes the variability of \lstinline!a! in account, see \cref{variability-of-structured-entities}.
+Regarding variability, slicing (see \cref{slice-operation}) is interpreted as syntactic sugar for such a construct, so \lstinline!a.x! and \lstinline!a[:].x! for a vector \lstinline!a! has the same variability as \lstinline!a[1:size(a,1)].x!.
+
 \begin{example}
 The (underdetermined) model \lstinline!Test! below illustrates two kinds of consequences due to variability constraints.
 First, it contains variability errors for declaration equations and assignments.