English

On the Pythagoras number for polynomials of degree 4 in 5 variables

Algebraic Geometry 2023-06-12 v1

Abstract

We give an example of a polynomial of degree 4 in 5 variables that is the sum of squares of 8 polynomials and cannot be decomposed as the sum of 7 squares. This improves the current existing lower bound of 7 polynomials for the Pythagoras number p(5,4)p(5,4).

Keywords

Cite

@article{arxiv.2306.05959,
  title  = {On the Pythagoras number for polynomials of degree 4 in 5 variables},
  author = {Santiago Laplagne},
  journal= {arXiv preprint arXiv:2306.05959},
  year   = {2023}
}