Sums of three squares and Noether-Lefschetz loci
Algebraic Geometry
2019-02-20 v2
Abstract
We show that the set of real polynomials in two variables that are sums of three squares of rational functions is dense in the set of those that are positive semidefinite. We also prove that the set of real surfaces in P^3 whose function field has level 2 is dense in the set of those that have no real points.
Keywords
Cite
@article{arxiv.1706.02053,
title = {Sums of three squares and Noether-Lefschetz loci},
author = {Olivier Benoist},
journal= {arXiv preprint arXiv:1706.02053},
year = {2019}
}
Comments
17 pages, presentation improved