On the class groups of certain imaginary cyclic fields of 2-power degree

Abstract

Let p be an odd prime number and 2e+1 be the highest power of 2 dividing p − 1. For 0 ≤ n ≤ e, let kn be the real cyclic field of conductor p and degree 2n. For a certain imaginary quadratic field L0, we put Ln = L0kn. For 0 ≤ n ≤ e − 1, let Fn be the imaginary quadratic subextension of the imaginary (2, 2)-extension Ln+1/kn with Fn ̸= Ln. We study the Galois module structure of the 2-part of the ideal class group of the imaginary cyclic field Fn. This generalizes a classical result of Rédei and Reichardt for the case n = 0.