Urgent answer required for these questions please!

(3) Let G be a finite group and let element a in Aut(G) be an automorphism og G. Let X be an element of Irr(G) be an irreducible character of G.

Define (X)^a(g) := X(g^a). Is (X)^a irreducible?

Printable View

- May 11th 2011, 01:46 PMTurloughmackCharacter Theory II
Urgent answer required for these questions please!

(3) Let G be a finite group and let element a in Aut(G) be an automorphism og G. Let X be an element of Irr(G) be an irreducible character of G.

Define (X)^a(g) := X(g^a). Is (X)^a irreducible? - May 11th 2011, 06:30 PMDrexel28
Think back to what irreducible characters are--they are the characters of irreps on . So, let and let be the irrep it came from. Then, as you can easily verify as you denoted is the character of (which is a representation since ). Now, if left any non-trivial proper subspace of -invariant wouldn't it be necessary (using the fact that is bijective) that same subspace would be -invariant? So...