Polynomial Dedekind domains with finite residue fields of prime characteristic (2207.04280v3)

Abstract: We show that every Dedekind domain $R$ lying between the polynomial rings $\mathbb Z[X]$ and $\mathbb Q[X]$ with the property that its residue fields of prime characteristic are finite fields is equal to a generalized ring of integer-valued polynomials, that is, for each prime $p\in\mathbb Z$ there exists a finite subset $E_p$ of transcendental elements over $\mathbb Q$ in the absolute integral closure $\overline{\mathbb Z_p}$ of the ring of $p$-adic integers such that $R={f\in\mathbb Q[X]\mid f(E_p)\subseteq \overline{\mathbb Z_p}, \forall \text{ prime }p\in\mathbb Z}$. Moreover, we prove that the class group of $R$ is isomorphic to a direct sum of a countable family of finitely generated abelian groups. Conversely, any group of this kind is the class group of a Dedekind domain $R$ between $\mathbb Z[X]$ and $\mathbb Q[X]$.