Determine all the permutations $\sigma \in S_5$ that commute with the permutation $\alpha = (1 \space 2)(3 \space 4 \space 5).$
Asked
Active
Viewed 208 times
0
H. Daniel
- 21
-
Same as this question, or this one etc. – Dietrich Burde Sep 04 '17 at 18:33
1 Answers
0
Hint: $\varphi\in S_n$ then $$\varphi(a_1,a_2,\cdots,a_k)\varphi^{-1}=(\varphi(a_1),\cdots,\varphi(a_k)).$$
Suppose $\varphi\in S_5$ such that $\varphi\sigma \varphi^{-1}=\sigma$ then $\varphi(1)=1,2$ and hence $\varphi(2)=2,1$.
Similarly for $(3,4,5)$.
Nirvanacs
- 1,523
- 9
- 14