An octonion algebra originating in combinatorics
Rings and Algebras
2010-12-24 v2 Combinatorics
Abstract
C.H. Yang discovered a polynomial version of the classical Lagrange identity expressing the product of two sums of four squares as another sum of four squares. He used it to give short proofs of some important theorems on composition of delta-codes (now known as T-sequences). We investigate the possible new versions of his polynomial Lagrange identity. Our main result shows that all such identities are equivalent to each other.
Keywords
Cite
@article{arxiv.1002.2752,
title = {An octonion algebra originating in combinatorics},
author = {D. Z. Djokovic and K. Zhao},
journal= {arXiv preprint arXiv:1002.2752},
year = {2010}
}
Comments
11 pages, A simpler proof of the main theorem, due to Alberto Elduque, is inserted. The paper will appear in the Proc. Amer. Math. Soc