Recent content by mansolo

Let A be an (n x n) upper Hessenberg matrix with the following constraints: a_{j,j} < 0 , j=1,...,n a_{j,j}= - sum a_{i,j} [i≠j] , j=1,...,n-1 a_{n,n} > - sum a_{i,n} [i≠n] Example: -1 2 0 2 0 1 -5 4 0 0 0 3 -9 1 0 0 0...