-The edges from the source or to the sink, or between these pairs, are
-of length zero, and the edge between the two nodes of such a pair has
-a length equal to the opposite of the detection score.
+The MTPTracker is a wrapper around the MTPGraph class. From the
+defined spatial topology and number of time steps, it builds a graph
+with one source, one sink, and two nodes per location and time. The
+edges from the source or to the sink, or between these pairs of nodes,
+are of length zero, and the edges between the two nodes of such a pair
+have negative lengths, equal to the opposite of the corresponding
+detection scores. This structure also ensures that the trajectories
+computed by the MTPTracker will be node-disjoint, since the
+trajectories computed by the MTPGraph are edge-disjoint.