Corollary4.4:LetS-{n1°a1,n2°a2y…,n1°at} andn;≥ r for each i=1,2,…,n, then the number of r-permutations of s is kr▪ Corollary 4.4: Let S={n1 •a1 ,n2 •a2 ,…,nk •ak }， and ni r for each i=1,2,…,n，then the number of r-permutations of S is kr