Change 'non-record elements' to recursive formulation

chapters/operatorsandexpressions.tex

@@ -1506,7 +1506,7 @@ \subsection{Discrete-Time Expressions}\label{discrete-time-expressions}
 \end{nonnormative}
 
 For a scalar or array equation \lstinline!expr1 = expr2! where neither expression is of base type \lstinline!Real!, both expressions must be discrete-time expressions.
-For a record equation, the same rule applies to the non-record elements of the equation.
+For a record equation, the rule applies recursively to each of the components of the record.
 This is called the \firstuse{discrete-valued equation variability rule}\index{discrete-valued equation variability rule}.
 
 \begin{nonnormative}