det(hilbert(80),rational_det);
  
  h40:=hilbert(40);
  hinv:=inverse(hilbert(40),rational_det); 
  hinv*h40;
  
  h70:=hilbert(70);
  hinv:=inverse(hilbert(70),rational_det);
  hinv*h70;
  
  
  purge(h40);
  purge(h70);
  purge(hinv);