There was a few inaccuracies ¡­

There was a few inaccuracies in the note about the alternating groups being simple. Two errors in the proof of theorem 2. A misprint in problem 5 a) and a stupid hint for problem 5 b). Corrected version on the web.

I also have split problem 5 b) in two parts, to make it easier to give a hint.

Geir