2.6.15. Related
Denotes that a constraint and a constraint are related by a specific reason that is not covered by an existing link.
EXAMPLE: As an example, the constraint (i.e., given a digraph, partition it so that each vertex belongs to one tree for which the difference between the longest and the shortest paths – from a leaf to the root – is restricted) is related to the constraint (i.e., given a set of variables, restrict the difference between the number of occurrence of the value that occurs the most and the value that occurs the least) by the fact that, on the one hand the constraint can express a balanced tree, on the other side the constraint can express a balanced assignment.