English

Anisotropy and the integral closure

Commutative Algebra 2015-09-08 v1 Number Theory

Abstract

Let K be a number field and let A be an order in K. The trace map from K to Q induces a non-degenerate symmetric bilinear form <,>: B x B \to Q/Z where B is a certain finite abelian group of size \Delta(A). In this article we discuss how one can obtain information about \mathcal{O}_K by purely looking at this symmetric bilinear form. The concepts of anisotropy and quasi-anisotropy, as defined in another article by the author, turn out to be very useful. We will for example show that under certain assumptions one can obtain \mathcal{O}_K directly from <,>. In this article we will work in a more general setting than we have discussed above. We consider orders over Dedekind domains.

Keywords

Cite

@article{arxiv.1109.6733,
  title  = {Anisotropy and the integral closure},
  author = {Michiel Kosters},
  journal= {arXiv preprint arXiv:1109.6733},
  year   = {2015}
}

Comments

21 pages

R2 v1 2026-06-21T19:13:01.008Z