### 2.6.15. Related

Denotes that a constraint ${C}_{\mathrm{𝑒𝑛𝑡𝑟𝑦}}$ and a constraint ${C}_{\mathrm{𝑎𝑙𝑠𝑜}}$ are related by a specific reason that is not covered by an existing link.

EXAMPLE: As an example, the constraint ${C}_{\mathrm{𝑎𝑙𝑠𝑜}}=$ $\mathrm{𝚝𝚛𝚎𝚎}_\mathrm{𝚛𝚊𝚗𝚐𝚎}$ (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 ${C}_{\mathrm{𝑒𝑛𝑡𝑟𝑦}}=$ $\mathrm{𝚋𝚊𝚕𝚊𝚗𝚌𝚎}$ (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 $\mathrm{𝚝𝚛𝚎𝚎}_\mathrm{𝚛𝚊𝚗𝚐𝚎}$ can express a balanced tree, on the other side the constraint $\mathrm{𝚋𝚊𝚕𝚊𝚗𝚌𝚎}$ can express a balanced assignment.