OK, I have just been checking the order of an automorphism and it is actually quite straightforward - definition is as follows:

If the automorphism is as in the exercise that we are focused on, then the order is the smallest such that where E is the identity function.

OK so in the exercise we have that is obviously of order 2.

However I am still unable to show that K[I] = K + KI 'extends' (?) to the inner automorphism specified.

I would very much appreciate some help.

Peter

[This has also been posted on MHB]