ordinal number
mathematics
Quick Summary
An ordinal number designates the place of an item in an ordered sequence, such as first, second, or third. It specifies both the position and the quantity of elements within that sequence. Ordinal numbers are fundamental in mathematics, particularly in set theory, where they are used to determine positions within a well-ordered sequence, contrasting with cardinal numbers that indicate the size of a set. The concept extends to transfinite numbers, allowing for the ordering of infinite sets.12
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