out tt;
%off nat;

depend ap,zp;
depend am,zm;

h:=mat((1,0),(0,-1));
xp:=mat((0,1),(0,0));
xm:=mat((0,0),(1,0));


Mp:=mat((1,ap),(0,1));
Mm:=mat((1,0),(am,1));


MM:=(MP**-1)*MM;
ro:=log( - df(log(MM(1,1)),zp,zm) );

%-----------------------------------------

ap:=zp;
am:=zm;

ro:=log( - df(log(MM(1,1)),zp,zm) );
df(ro,zp,zm) - 2*exp(ro);


shut tt;
bye;
end;