English

Elasticities of Orders in Central Simple Algebras

Rings and Algebras 2021-10-18 v1 Number Theory

Abstract

Let O\mathcal{O} be an order in a central simple algebra AA over a number field. The elasticitity ρ(O)\rho(\mathcal{O}) is the supremum of all fractions k/lk/l such that there exists an non-zero-divisor aOa \in \mathcal{O} that has factorizations into atoms (irreducible elements) of length kk and ll. We characterize the finiteness of the elasticity for Hermite orders O\mathcal{O}, if either O\mathcal{O} is a quaternion order, or O\mathcal{O} is an order in an central simple algebra of larger dimension and Op\mathcal{O}_{\mathfrak{p}} is a tiled order at every finite place p\mathfrak{p} at which ApA_{\mathfrak{p}} is not a division ring. We also prove a transfer result for such orders. This extends previous results for hereditary orders to a non-hereditary setting.

Keywords

Cite

@article{arxiv.2110.08047,
  title  = {Elasticities of Orders in Central Simple Algebras},
  author = {Casper Barendrecht},
  journal= {arXiv preprint arXiv:2110.08047},
  year   = {2021}
}