Constraint LexDecreasing
The constraint Decreasing can be naturally lifted to lists, by considering the so-called lexicographic order: it is then called LexDecreasing and ensures that the tuple formed by the values assigned to the variables of a first list is lexicographically greater than (or equal to) the tuple formed by the values assigned to the variables of a second list.
As this constraint is totally symmetric to constraint LexIncreasing, we invite the reader to see the page concerning it.