Published online by Cambridge University Press: 20 November 2018
We construct unconditionally several families of number fields with the largest possible class numbers. They are number fields of degree 4 and 5 whose Galois closures have the Galois group ${{A}_{4}},\,{{S}_{4}}$, and ${{S}_{5}}$. We first construct families of number fields with smallest regulators, and by using the strong Artin conjecture and applying the zero density result of Kowalski–Michel, we choose subfamilies of $L$-functions that are zero-free close to 1. For these subfamilies, the $L$-functions have the extremal value at $s\,=\,1$, and by the class number formula, we obtain the extreme class numbers.