This sentence is from The World of Zhuangzi, which was put forward by Zhuangzi.

"A hammer of one foot, half a day's work, is inexhaustible." "One-foot hammer" takes half today, half tomorrow and half the day after tomorrow. If you take half every day, you will always leave half, so "it is inexhaustible." A foot hammer is a finite object, but it can be divided infinitely. This debate is about the unity of finite and infinite, and there is infinity in finite. This is a dialectical thought.

It can be described in mathematical language about limit. Let {Xn} be an infinite sequence. If there is a constant a for any given positive number ε (no matter how small it is), there is always a positive integer n, so that when n >: all Xn, when n has the inequality | xn-a |.

Lim Xn = a or Xn→a(n→∞)

If the sequence has no limit, it is said that the sequence diverges.