Quadratic fields with noncyclic 5- or 7-class groups
The author proves: If \(g\in\{5,7\}\) then the number of quadratic fields with absolute discriminant \(\leq x\) and ideal class group having a subgroup isomorphic to \(\mathbb{Z}/g\mathbb{Z}\times\mathbb{Z}/g\mathbb{Z}\) is \(\gg x^{\frac14}\).
scientific article; zbMATH DE number 5636947