function Sep30()

% Let s be the  (p,q) entry of conj(F)*F. Thus

%     s = sum_{k=0}^{n-1} omega^(-kp)*omega^(kq) 
%       = sum_{k=0}^{n-1) omega^(k(q-p)
%
% Thus (1-omega)*s = (1 - omega^(n(q-p))

% If q is different from p, then conclude that s = 0.
% If q = p, conclude that s = n.