Almost

In other words, an infinite set S that is a subset of another infinite set L, is almost L if the subtracted set L\S is of finite size.

This is conceptually similar to the Almost everywhere concept of Measure theory.

Examples:

• The set <math> S = \{ n \in \mathbf{N} | n \ge k \} </math> is almost N for any k in N, because only finitely many natural numbers are less than k.
• The set of prime numbers is not almost N because there are infinitely many natural numbers that are not prime numbers.