Turn 'Sorting of a simulation model' into non-normative \subsubsection

chapters/synchronous.tex

@@ -607,16 +607,19 @@ \subsection{Base-clock conversion operators}\label{base-clock-conversion-operato
 \end{lstlisting}
 
 The value of \lstinline!yc! at the first clock tick is $\text{\lstinline!yc!} = 2$ (and not $\text{\lstinline!yc!} = 1$).  The reason is that the continuous-time model \lstinline!der(y) + y = 2! is first initialized and after initialization \lstinline!y! has the value 2.  At the first clock tick at $\text{\lstinline!time!} = 0$, the left limit of \lstinline!y! is 2 and therefore $\text{\lstinline!yc!} = 2$.
+\end{example}
 
-\paragraph*{Sorting of a simulation model}
+\subsubsection{Sorting of a simulation model}
 
+\begin{nonnormative}
 Since \lstinline!sample(u)! returns the left limit of \lstinline!u!, and the left limit of \lstinline!u! is a known value, all inputs to a base-clock partition are treated as known during sorting.
 Since a periodic and interval clock can tick at most once at a time instant, and since the left limit of a variable does not change during event iteration (i.e., re-evaluating a base-clock partition associated with a condition clock always gives the same result because the \lstinline!sample(u)! inputs do not change and therefore need not to be re-evaluated) all base-clock partitions, see \cref{base-clock-partitioning}, need not to be sorted with respect to each other.
 Instead, at an event instant, active base-clock partitions can be evaluated first (and once) in any order.
 Afterwards, the continuous-time partition is evaluated.
+
 Event iteration takes place only over the continuous-time partition.
 In such a scenario, accessing the left limit of \lstinline!u! in \lstinline!sample(u)! just means to pick the latest available value of \lstinline!u! when the partition is entered, storing it in a local variable of the partition and only using this local copy during evaluation of the equations in this partition.
-\end{example}
+\end{nonnormative}
 
 \subsection{Sub-clock conversion operators}\label{sub-clock-conversion-operators}