AlephNull

Aleph-null, often denoted as ℵ₀, is a mathematical concept representing the smallest type of infinity. It specifically describes the size of a set that can be counted, like the set of all natural numbers (0, 1, 2, 3, etc.). While it’s infinite, it’s a “countable infinity,” meaning you can list its elements one by one, even though there are infinitely many. Aleph-null contrasts with larger infinities, such as the set of real numbers, which cannot be listed in this way. Understanding aleph-null helps in grasping how mathematicians categorize different sizes of infinity in set theory.