Exercise
Let G be the group S3.
Consider the
conjugation representation
C : G -> Sym({e, a, b, c,
y, z}),
where
y = (1,2,3), z = (1,3,2),
a = (1,2), b = (2,3), c = (1,3).
How many choices of invariant subsets are there in G?
1
2
4
8
No.
The empty and the full set already make two.
No, the empty, the full set and {e} already make three.
No.
Determine the minimal invariant subsets first.
Yes. There are three minimal invariant subsets:
-
{e}
- {a, b, c}
- {y, z}
Now any union of a choice from these three makes up an invariant subset.