English

Integer-valued polynomials on discrete valuation rings of global fields with prescribed lengths of factorizations

Number Theory 2023-08-25 v2 Commutative Algebra

Abstract

Let VV be a valuation ring of a global field KK. We show that for all positive integers kk and 1<n1nk1 < n_1 \leq \ldots \leq n_k there exists an integer-valued polynomial on VV, that is, an element of Int(V)={fK[X]f(V)V}\text{Int}(V) = \{ f \in K[X] \mid f(V) \subseteq V \}, which has precisely kk essentially different factorizations into irreducible elements of Int(V)\text{Int}(V) whose lengths are exactly n1,,nkn_1,\ldots,n_k. In fact, we show more, namely that the same result holds true for every discrete valuation domain VV with finite residue field such that the quotient field of VV admits a valuation ring independent of VV whose maximal ideal is principal or whose residue field is finite. If the quotient field of VV is a purely transcendental extension of an arbitrary field, this property is satisfied. This solves an open problem proposed by Cahen, Fontana, Frisch and Glaz in these cases.

Keywords

Cite

@article{arxiv.2206.11003,
  title  = {Integer-valued polynomials on discrete valuation rings of global fields with prescribed lengths of factorizations},
  author = {Victor Fadinger and Sophie Frisch and Daniel Windisch},
  journal= {arXiv preprint arXiv:2206.11003},
  year   = {2023}
}