人の数学では”So in the following sequence: 0, 1, 2, …, ω, ω+1 ω is a limit ordinal because for any smaller ordinal (in this example, a natural number) there is another ordinal (natural number) larger than it, but still less than ω.”
https://en.wikipedia.org/wiki/Ordinal_number Ordinal number
In set theory, an ordinal number, or ordinal, is one generalization of the concept of a natural number that is used to describe a way to arrange a (possibly infinite) collection of objects in order, one after another.
An ordinal number is used to describe the order type of a well-ordered set (though this does not work for a well-ordered proper class). A well-ordered set is a set with a relation < such that: (Trichotomy) For any elements x and y, exactly one of these statements is true: ・x < y ・y < x ・x = y
Successor and limit ordinals So in the following sequence: 0, 1, 2, …, ω, ω+1 ω is a limit ordinal because for any smaller ordinal (in this example, a natural number) there is another ordinal (natural number) larger than it, but still less than ω. (引用終り) 以上
