1.1 --- a/doc/lgf.dox	Tue Nov 16 08:19:11 2010 +0100
     1.2 +++ b/doc/lgf.dox	Thu Nov 25 22:45:29 2010 +0100
     1.3 @@ -63,11 +63,28 @@
     1.4   3      (40,10)      10      "Third node"
     1.5  \endcode
     1.6  
     1.7 -The \c \@arcs section is very similar to the \c \@nodes section, it
     1.8 -again starts with a header line describing the names of the maps, but
     1.9 -the \c "label" map is not obligatory here. The following lines
    1.10 -describe the arcs. The first two tokens of each line are the source
    1.11 -and the target node of the arc, respectively, then come the map
    1.12 +The \e LGF files can also contain bipartite graphs, in this case a
    1.13 +\c @red_nodes and a \c @blue_nodes sections describe the node set of the
    1.14 +graph. If a map is in both of these sections, then it can be used as a
    1.15 +regular node map.
    1.16 +
    1.17 +\code
    1.18 + @red_nodes
    1.19 + label  only_red_map   name
    1.20 + 1      "cherry"       "John"
    1.21 + 2      "Santa Claus"  "Jack"
    1.22 + 3      "blood"        "Jason"
    1.23 + @blue_nodes
    1.24 + label  name
    1.25 + 4      "Elisabeth"
    1.26 + 5      "Eve"
    1.27 +\endcode
    1.28 +
    1.29 +The \c \@arcs section is very similar to the \c \@nodes section,
    1.30 +it again starts with a header line describing the names of the maps,
    1.31 +but the \c "label" map is not obligatory here. The following lines
    1.32 +describe the arcs. The first two tokens of each line are
    1.33 +the source and the target node of the arc, respectively, then come the map
    1.34  values. The source and target tokens must be node labels.
    1.35  
    1.36  \code