21/12/23 07:22:47.56 ypzkaLik.net
メモ
URLリンク(encyclopediaofmath.org)
Ordinal number
transfinite number, ordinal
The order type of a well-ordered set. This notion was introduced by G. Cantor in 1883 (see [2]). For instance, the ordinal number of the set N of all positive integers, ordered by the relation ≦, is ω.