Use new terminology (again).

chapters/connectors.tex

@@ -911,23 +911,23 @@ \subsection{Generation of Connection Graph Equations}\label{generation-of-connec
 \subsubsection{Remove Redundant Connect-Equations}
 In order to eliminate any redundant \lstinline!connect!-equation the following preparation is needed.
 \begin{nonnormative}
-In the common case where there are no redundant \lstinline!connect!-equations a \lstinline!connect! between connectors with \emph{one} overdetermined component will directly generate \emph{one} breakable branch.
+In the common case where there are no redundant \lstinline!connect!-equations a \lstinline!connect! between connectors with \emph{one} overdetermined component will directly generate \emph{one} optional spanning-tree edge.
 \end{nonnormative}
 \begin{enumerate}
 \item
   The connection sets are built similarly to the normal way, but keeping the overdetermined components as primitives.
 \item
-  Instead of generating the equality-equation for an overdetermined component, a breakable branch in the virtual connection graph is constructed.
+  Instead of generating the equality-equation for an overdetermined component, an optional spanning-tree edge in the virtual connection graph is constructed.
 \end{enumerate}
 If a connection set contains $n$ overdetermined components, and was built from $m$ \lstinline!connect!-equations, then $m-n-1$ of the \lstinline!connect!-equations are redundant.
-If there are no redundant \lstinline!connect!-equations (i.e., if $m=n-1$), the breakable branches can be chosen to correspond to the \lstinline!connect!-equations for overdetermined connectors.
-If there are redundant \lstinline!connect!-equations there will always exist \lstinline!connect!-equations without a corresponding breakable branch.
+If there are no redundant \lstinline!connect!-equations (i.e., if $m=n-1$), the optional spanning tree edges can be chosen to correspond to the \lstinline!connect!-equations for overdetermined connectors.
+If there are redundant \lstinline!connect!-equations there will always exist \lstinline!connect!-equations without a corresponding optional spanning tree edge.
 \begin{nonnormative}
 They are called redundant since if they were removed the same connection set and equations would be generated.
 Redundant \lstinline!connect!-equations include directly connecting a connector to itself, duplicated connections, and one connection among all of the pair-wise connections between \lstinline!a!, \lstinline!b!, and \lstinline!c!.
 The latter case can be used to consistently handle conditional components (so that disabling \lstinline!b! does not break the connection between \lstinline!a! and \lstinline!c!).
 \end{nonnormative}
-The selected breakable branches, together with all nonbreakable branches generated from \lstinline!Connections.branch!, and nodes corresponding to definite and potential roots from the virtual connection graph.
+The selected optional spanning tree edges, together with all required spanning tree edges generated from \lstinline!Connections.branch!, and nodes corresponding to definite and potential roots from the virtual connection graph.
 
 \subsubsection{Spanning Trees}
 Before connection equations are generated, the virtual connection graph is transformed into a set of spanning trees by removing optional spanning tree edges from the graph.
@@ -938,15 +938,15 @@ \subsubsection{Spanning Trees}
 \begin{enumerate}
 \item
   Every definite root node defined via the \lstinline!Connections.root!-equation is a root of one spanning tree.
-  It is an error if two (or more) definite root nodes are connected through nonbreakable branches.
+  It is an error if two (or more) definite root nodes are connected through required spanning tree edges.
 \item
   The virtual connection graph may consist of sets of subgraphs that are not connected together.
   Every subgraph in this set shall have at least one definite root node or one potential root node in a simulation model.
   If a graph of this set does not contain any definite root node, then one potential root node in this subgraph that has the lowest priority number is selected to be the root of that subgraph.
   The selection can be inquired in a class with function \lstinline!Connections.isRoot!, see table above.
 \end{enumerate}
 \item
-  If there is a cycle among nonbreakable branches it is an error, as it is not possible to construct a spanning tree.
+  If there is a cycle among required spanning-tree-edges it is an error, as it is not possible to construct a spanning tree.
 \item
   For a subgraph with $n$ selected roots, optional spanning-tree edges are removed such that the result is a set of $n$ spanning trees with the selected root nodes as roots.
 \end{enumerate}
@@ -969,7 +969,7 @@ \subsection{Examples}\label{examples-of-overconstrained-connectors}
   \begin{center}
     \includegraphics{overdetermined}
   \end{center}
-  \caption{Example of a virtual connection graph.}
+  \caption{Example of a virtual connection graph. Breakable branches refer to optional spanning-tree edges, and nonbreakable to required spanning-tree edges.}
 \end{figure}
 \end{example}