Given finite fields F < E, we
present a collection of subgroups C ≤ E× and establish, to each C, a Galois
connection between the intermediate field lattice ℰ = {L∣F ≤ L ≤ E} and C’s
subgroup lattice. Our main result is that, in all but an extremely limited and
completely determined family, the closed subset of ℰ is ℰ itself, establishing a natural
bijection between ℰ and the lattice {L ∩ C∣L ∈ℰ}. As an application, we use this
bijection to calculate the set of degrees for the complex-valued irreducible
representations of the split extension C ⋊Gal(E∕F).
Keywords
Galois correspondence, lattice, character degree, finite
field