4.4 Permutations and combinations of multisets 4.4.1 Permutations of multisets If s is a multiset, a r-permutation of s is an ordered arrangement of r of the objects of s. If the total number of objects of s is n, then a n-permutation of S will also be called a permutation of s For example, if S=2.a, 1.b, 3.c, then aacb acbc cacc are 4-permutations of s abcca is a permutation of s The multiset s has no 7-permutations since >2+1+3=6. the number of obiects of s4.4 Permutations and Combinations of multisets ▪ 4.4.1 Permutations of multisets ▪ If S is a multiset, a r-permutation of S is an ordered arrangement of r of the objects of S. If the total number of objects of S is n，then a n-permutation of S will also be called a permutation of S. ▪ For example, if S={2•a,1•b,3•c}, then ▪ aacb acbc cacc are 4-permutations of S, ▪ “abccac” is a permutation of S. ▪ The multiset S has no 7-permutations since 7>2+1+3=6, the number of objects of S