What is an enupla?

An enupla is an ordered sequence of no Elements. It is also known as n-double, n-tuple or simply tuple.

When n = 2, we can call the sequence double. For example, (1,2) is a double. Already the sequence (-2, 1) is another double.

Therefore, what differs a number from a set is that:
- An enuple can contain an object more than once.
- Objects are necessarily represented in the given order.