# Almost - Wikipedia Mobile

Use Wikipedia with dynamical search help in all languages ...
English |German | Spanish | French

## Wikipedia

Wikipedia - How to create a page In set theory, when dealing with sets of infinite size, the term almost or nearly is used to refer to all but a negligible amount of elements in the set. The notion of "negligible" depends in the context, and may mean "of measure zero" (in a measure space), "countable" (when uncountably infinite sets are involved), or "finite" (when infinite sets are involved).

For example:

• The set $S=\{n\in \mathbb {N} \,|\,n\geq k\}$ is almost $\mathbb {N}$ for any $k$ in $\mathbb {N}$ , because only finitely many natural numbers are less than $k$ .
• The set of prime numbers is not almost $\mathbb {N}$ , because there are infinitely many natural numbers that are not prime numbers.
• The set of transcendental numbers are almost $\mathbb {R}$ , because the algebraic real numbers form a countable subset of the set of real number (the latter of which is uncountable).
• The Cantor set is uncountably infinite, but has Lebesgue measure zero. So almost all real numbers in (0, 1) are member of the complement of the Cantor set.

## Andere Versionen: Mobilpedia | Sick Universe