Constraint nvalue It is defined in the catalog as follows:
nvalue(NVAL,VARIABLES) NVAL dvar VARIABLES collection(var:var)
As an illustration, we can have in XML:
<constraint name="C1" arity="5" scope="V0 V1 V2 V3 V4" reference="global:nvalue">
<parameters>
V0
[ V1 V2 V3 V4 ]
</parameters>
</constraint>
Constraint nvalues It is defined in the catalog as follows:
nvalues(VARIABLES,RELOP,LIMIT)
VARIABLES collection(var:dvar)
RELOP atom LIMIT dvar RELOP in {eq,ne,ge,gt,le,lt}
As an illustration, we can have in XML:
<constraint name="C1" arity="5" scope="V0 V1 V2 V3 V4" reference="global:nvalues">
<parameters>
[ V1 V2 V3 V4 ] <gt/>
V0
</parameters>
</constraint>

## 3.7 Illustrations

In Figures 2 and 3, one can see the XML representation of the 4*-queens* instance. In Figures 4, 5 and 6, one can see the XML representation of a CSP instance involving 5 variables and the 5 following constraints:
- C0: X0 6= X1
- C1: X3 − X0 ≥ 2
- C2: X2 − X0 = 2 - C3: X1 + 2 = |X2 − X3|
- C4: X1 6= X4 Finally, in Figures 7 and 8, one can see the XML representation of the 3magic square instance. The global constraints *weightedSum* and *allDifferent* are used.