问题4.1:你能一眼看出这个结论吗? Since (a1,a2,.,an)=(a1an)(a1an-1)…(a1a3)(a1a2) any cycle can be written as the product of transpositions 问题4.2:上述结论如何导致这个命题的? Proposition 5.4 Any permutation of a finite set containing at least two elements can be written as the product of transpositions. 问题5:你能很快地给出一个置换的逆是什么吗?问题4.1:你能一眼看出这个结论吗? 问题4.2:上述结论如何导致这个命题的? 问题5:你能很快地给出一个置换的逆是什么吗?