### 2.5.21. Used in graph description

Constraint ${C}_{\mathrm{𝑎𝑙𝑠𝑜}}$ is used within a graph based description of constraint ${C}_{\mathrm{𝑒𝑛𝑡𝑟𝑦}}$.

EXAMPLE: As an example, the constraint ${C}_{\mathrm{𝑎𝑙𝑠𝑜}}=$ $\mathrm{𝚝𝚠𝚘}_\mathrm{𝚘𝚛𝚝𝚑}_\mathrm{𝚍𝚘}_\mathrm{𝚗𝚘𝚝}_\mathrm{𝚘𝚟𝚎𝚛𝚕𝚊𝚙}$, a constraint enforcing the fact that two orthotopesAn orthotope corresponds to the generalisation of a segment, a rectangle and a box to the $n$ -dimensional case. do not overlap, is used in the graph based description of the constraint ${C}_{\mathrm{𝑒𝑛𝑡𝑟𝑦}}=$ $\mathrm{𝚍𝚒𝚏𝚏𝚗}$. Given a collection of orthotopes, the $\mathrm{𝚍𝚒𝚏𝚏𝚗}$ constraint enforces for each pair of orthotopes $\left({O}_{1},{O}_{2}\right)$ the fact that ${O}_{1}$ and ${O}_{2}$ do not overlap.