make dummy attribute more clear

doc/chapter/2architecture.tex

@@ -50,13 +50,13 @@ The internal representation of graphs is further explained in the section~\ref{s
     name & string & yes & If not omitted, this must be unique for a given parent node. \\\hline
     width & integer & yes & The minimum width of the node.
     The node can be wider if it contains other nodes that need more space.
-    If the whole layout is too large, it is resized, such that all nodes are proportionately shrunk: In that case the minimum width can be undercut.
+    If the whole layout is too large, it is resized, such that all nodes are proportionately shrunk: In that case the minimum width can be exceeded after the shrinking.
     Default 40.\\\hline
     height & integer & yes & The minimum height of the node.
     The node can be higher if it contains other nodes that need more space.
-    If the whole layout is too large, it is resized, such that all nodes are proportionately shrunk: In that case the minimum height can be undercut.
+    If the whole layout is too large, it is resized, such that all nodes are proportionately shrunk: In that case the minimum height can be exceeded after the shrinking.
     Default 40.\\\hline
-    dummy & boolean & yes & Iff this is set to yes, then the node is a dummy node. \\\hline
+    dummy & boolean & yes & Iff this is explicitly set to yes, then the node is a dummy node. \\\hline
     layers & < < node > > & yes & The layers of nodes inside this node (Hierarchy). \\\hline
     edges & < edge > & yes & The edges between nodes whose parent node is this node. \\\hline
     \caption[Node Attributes]{Node Attributes. < \emph{element type} > is a list.}