Given the sequence {Xn}, arbitrarily select infinite items from it, and the sequence formed according to the original order is called a sub sequence of the sequence {Xn}.
The subsequence is a sequence of numbers, and it is convergent or divergent with any ordinary subsequence, and has the same limit when it converges.
Chinese name
Child column
Definition
A sequence of numbers formed by randomly selecting infinite terms from them in the original order
