[squeaky-clean]

It doesn't though. How would merge sort become constant time if you assume a maximum value? It's also a joke...

[libealistand]

The main "value" in the domain of sorting problems is the number of elements in your collection.

A subproblem also considers the elements to be integers, then they become another "value" domain. (But in general, sorting problems only need their elements to be comparable, not necessarily integers.)