Aleph One

Aleph-one, often denoted as ℵ₁, is a concept in set theory related to the sizes of infinite sets. Specifically, it represents the smallest uncountable cardinal number, which means it is larger than all countable sets, such as the set of natural numbers. If the Continuum Hypothesis is true, ℵ₁ is also the cardinality of the set of real numbers. Essentially, it helps mathematicians understand different "sizes" of infinity and how they relate to each other, providing a framework for exploring the complexities of infinite quantities in mathematics.