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);