The local-global principle for symmetric determinantal representations of smooth plane curves in characteristic two
arXiv:1412.8343
Abstract
We give an application of Mumford's theory of canonical theta characteristics to a Diophantine problem in characteristic two. We prove that a smooth plane curve over a global field of characteristic two is defined by the determinant of a symmetric matrix with entries in linear forms in three variables if and only if such a symmetric determinantal representation exists everywhere locally. It is a special feature in characteristic two because analogous results are not true in other characteristics.
10 pages, minor changes following the referee's suggestions; A shorter version of this paper will appear in Journal of Pure and Applied Algebra. This longer version contains an additional section (Section 4) on computational results for conics and cubics