约瑟夫环是一个数学的应用问题：已知n个人（以编号1，2，3...n分别表示）围坐在一张圆桌周围。从编号为k的人开始报数，数到m的那个人出列；他的下一个人又从1开始报数，数到m的那个人又出列；依此规律重复下去，直到圆桌周围的人全部出列。-Josephus is the application of a mathematical problem: Given n individuals (numbered 1, 2, 3, ... n, respectively) sitting around a round table around. From number k people began to count off the number to m the man out of the line　his next person and from a number off, the man was out of the line number to m　so regularly repeated down until roundtable around of the people all of the columns.