I assume denotes a rotation and denotes a flip
note that
So, we want to find all values of i and j such that:
if
then
and
Which means the , which is only an integer when n is even.
Now you can do the case if , You should get that
Hi,
my question is, "for n = 3 or greater, show is trivial if n is odd and is {1, } if n is even."
Any help would be appreciated; we haven't learned anything advanced in class yet, just about cosets and lagrange's thm.
My initial attempt was to consider that if is in , then for all g.
if g=a then and if g=b
but from here I'm quite stuck.
Thanks!!