B3.5
Compute the character table for the group of even permutations of five elements. You may wish to follow the steps below.
(a) List the conjugacy classes in and their orders.
(b) acts on by permuting the standard basis vectors. Show that splits as , where is the trivial 1-dimensional representation and is irreducible.
(c) By using the formula for the character of the symmetric square ,
decompose to produce a 5-dimensional, irreducible representation, and find its character.
(d) Show that the exterior square decomposes into two distinct irreducibles and compute their characters, to complete the character table of .
[Hint: You can save yourself some computational effort if you can explain why the automorphism of , defined by conjugation by a transposition in , must swap the two summands of .]