The maximal unramified extensions of certain complex Abelian number fields
The maximal unramified extensions of certain complex Abelian number fields
We combine root discriminant bounds with a ramification argument to show unconditionally that Q(-7,61) has no nontrivial unramified extension, a result first proved by Yamamura under the generalized Riemann hypothesis (GRH). This renders unconditional his determination of the maximal unramified extensions of the complex quadratic fields with class number 2. …