Paper 2, Section II, I
Part II, 2013
For a positive integer , let be the cyclotomic field obtained by adjoining all -th roots of unity to . Let .
(i) Determine the Galois group of over .
(ii) Find all such that is contained in .
(iii) List all quadratic and quartic extensions of which are contained in , in the form or . Indicate which of these fields occurred in (ii).
[Standard facts on the Galois groups of cyclotomic fields and the fundamental theorem of Galois theory may be used freely without proof.]