Copositive matrices with circulant zero support set

Roland Hildebrand

Let $n\ge 5$ and let $u^1,\dots ,u^n$ be nonnegative real $n$-vectors such that the indices of their positive elements form the sets $\{1,2,\dots,n-2\},\{2,3,\dots,n-1\},\dots,\{n…