On equiangular lines in 17 dimensions and the characteristic polynomial of a Seidel matrix

Gary R. W. Greaves, Pavlo Yatsyna

For $e$ a positive integer, we find restrictions modulo $2^e$ on the coefficients of the characteristic polynomial ${\chi }_S(x)$ of a Seidel matrix $S$. We show that, for a Seidel matri…