find the centralizer Z(a) of the element a=(134) in S5

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- Feb 25th 2009, 05:05 AMwonjujincentralizer
find the centralizer Z(a) of the element a=(134) in S5

- Feb 26th 2009, 02:58 PMThePerfectHacker
Let be the conjugacy class of and let be the centralizer of that element. Then, the number of elements of is equal to the index of in . Now the number of conjugacy classes of is equal to . Therefore, the index of in is equal to . This tells us that has six elements. Let us see if we can figure them out through reasoning as opposed to mindless computation of all 120 elements in . First, certainly and so are all elements of the centralizer. Second, is a disjoint cycle from therefore . Thus, we see that all commute with . We found six elements, therefore, those elements mentioned above is the centralizer.