在排列组合中,有一类关于单调递增的映射个数的计数问题,本文对这类问题作一探讨.结论1已知两个实数集合A={x1,x2,…,xm}与B={y1,y2,…,yn},m≤n,若映射f:A→B满足f(x1),f(x2),…,f(xm)之间用k个“≤”号,m-k-1个“”号连接,0≤k≤m-1,则无论“≤”号与“”号的位置如何,这样 In the permutations and combinations, there is a class of counting problems concerning monotonically increasing number of mappings. This paper discusses such problems. Conclusion 1 Known two sets of real numbers A={x1,x2,...,xm} and B={ Y1,y2,...,yn},m≤n, if the mapping f:A→B satisfies f(x1), f(x2),...,f(xm) uses k “≤” signs, mk-1 “” is connected, 0≤k≤m-1, regardless of the position of “≤” and “”, so