👉 In mathematics, an ordinal is a type of cardinal number in set theory. Ordinals are used to distinguish between different types of sets and to classify them according to their size. Ordinal numbers can be defined as follows: - A countable ordinal is a well-ordered set. - An uncountable ordinal is neither countable nor finite. The first step towards defining an ordinal involves identifying the least cardinality (or "size") that an arbitrary set can have. This means assigning each element
