김장수

The group $S_n$ of permutations on $=\{1,2,\dots ,n\}$ is generated by simple transpositions $s_i=(i,i+1)$. The length $\ell (\pi )$ of a permutation $\pi$ is defined to be the minimum number of generators whose product is $\pi$. It is well-known that the longest element in \( …