For each global constraint entry of the catalogue, the slot See also provides links to other global constraints. Rather than just pointing to a set of constraints, we prefer to explicitly indicate the reason why we point to a given constraint. A link $\mathrm{𝑙𝑖𝑛𝑘}(C_{\mathrm{𝑒𝑛𝑡𝑟𝑦}},C_{\mathrm{𝑎𝑙𝑠𝑜}})$ from a constraint $C_{\mathrm{𝑒𝑛𝑡𝑟𝑦}}$ (i.e., the constraint associated with a catalogue entry) to another constraint $C_{\mathrm{𝑎𝑙𝑠𝑜}}$ (i.e., the constraint of the See also slot located in the catalogue entry of constraint $C_{\mathrm{𝑒𝑛𝑡𝑟𝑦}}$) has a given semantics and this section describes the kind of semantic links that are currently used. Before introducing each semantic link and its meaning, let us first quote that some of them are related by one of the following relations:

• A link $\mathrm{𝑙𝑖𝑛𝑘}$ is symmetric if and only if $\mathrm{𝑙𝑖𝑛𝑘}(C_1,C_2)\iff \mathrm{𝑙𝑖𝑛𝑘}(C_2,C_1)$.

• A link $\mathrm{𝑙𝑖𝑛𝑘}$ is asymmetric if and only if $\mathrm{𝑙𝑖𝑛𝑘}(C_1,C_2)\Rightarrow \neg \mathrm{𝑙𝑖𝑛𝑘}(C_2,C_1)$ ($\neg \mathrm{𝑙𝑖𝑛𝑘}(C_2,C_1)$ is a shortcut for denoting that the link $\mathrm{𝑙𝑖𝑛𝑘}(C_2,C_1)$ does not occur in the catalogue).

• A link ${\mathrm{𝑙𝑖𝑛𝑘}}_j$ is the converse of a link ${\mathrm{𝑙𝑖𝑛𝑘}}_i$ if and only if ${\mathrm{𝑙𝑖𝑛𝑘}}_i(C_1,C_2)\iff {\mathrm{𝑙𝑖𝑛𝑘}}_j(C_2,C_1)$.

Table 2.6.0 lists each semantic link and the relation it has.All links are automatically checked with respect to their relations each time the catalogue is generated. Then one section describes the meaning of each semantic link.