Answers are grounded in this paper and cite their sources.
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).
No takes yet. Share an insight, caveat, or question.
Santiago Laplagne (2024) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: