Permutations with restricted positions permutation r of [n derangement: i∈[ml,π()卡i generally:π(i1)≠j1,π(i2)≠j2,. forbidden positions Bc[m×[ml i∈[nl,(i,π(i)年BPermutations with restricted positions derangement: permutation ￾ of [n] ⇤i ￾ [n], ￾(i) ⇥= i generally: ￾(i1) ￾= j1, ￾(i2) ￾= j2,... B ⇥ [n] ￾ [n] ⇤i ￾ [n], (i, ￾(i)) ⇥￾ B forbidden positions