4.2.2 Permutations of sets &o An ordered arrangement of r elements of an n-element set is called an r-permutation o We denote by p(n, r) the number of r permutations of an n-element set Ifr>n, then p(n, r)=0. An n-permutation of an n-element set s is called a permutation ofs. A permutation of a set s is a listing of the elements of s in some order4.2.2 Permutations of sets ❖ An ordered arrangement of r elements of an n-element set is called an r-permutation. ❖ We denote by p(n,r) the number of r￾permutations of an n-element set. If r>n, then p(n,r)=0. An n-permutation of an n-element set S is called a permutation of S. A permutation of a set S is a listing of the elements of S in some order