The type of the elements in the set.

The chosen t must be infinite.

A total ordering function over the set elements. This is a two-argument function f such that:

• f e1 e2 is zero if the elements e1 and e2 are equal,
• f e1 e2 is strictly negative if e1 is smaller than e2,
• and f e1 e2 is strictly positive if e1 is greater than e2.