1. The problem statement, all variables and given/known data I have been given a 4x4 hessian matrix at a point c. I want to find out if the point is a local min/max/saddle. I am aware of the conditions of critical points for 3x3 hessians, but I'm not sure about 4x4 hessians. The hessian is given by 1 0 -2 1 0 2 0 -1 -2 0 5 2 1 -1 2 4 2. Relevant equations 3. The attempt at a solution I can get the determinant of the principal submatricies until the 3x3 matrix but is that enough to determine if its a local max min or saddle?