%off echo,nat$ off echo$ out "rreducparautom6_4N4.r"$ operator b$ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % The generic automorphism of g_{6,4} as in (art ijac1 section5) : phi:=mat((b(1,1),0,0,0,0,0), (0,b(2,2),0,0,0,0), (b(3,1),b(3,2),b(3,3),0,0,0), (b(4,1),b(4,2),0,b(2,2)*b(1,1),0,0), (b(5,1),b(5,2),b(5,3), -b(4,1)*b(2,2), b(2,2)**2*b(1,1), 0), (b(6,1),b(6,2),b(6,3), b(3,2)*b(1,1), 0, b(3,3)*b(1,1)))$ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % The generic nilpotent derivation as in (Cohomology tables page 116) : the eigenvalues % are 0 operator xi$ delta:= mat((0,0,0,0,0,0), (0,0,0,0,0,0), (xi(3,1),xi(3,2),0,0,0,0), (xi(4,1),xi(4,2),0,0,0,0), (xi(5,1),xi(5,2),xi(5,3),-xi(4,1),0,0), (xi(6,1),xi(6,2),xi(6,3),xi(3,2),0,0))$ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% write "The nonzero ajoints are delta(4,1), delta(5,2), delta(6,1), and delta(4,2)-delta(6,3)"$ write "Hence delta(4,2) and delta(6,3) are adjoint related"$ % by subtracting adjoints one then may suppose xi(4,1):=0$ xi(6,1):=0$ xi(5,2):=0$ xi(4,2):=0$ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% write "phi:=",phi; write "det(phi):=",det(phi); write "delta:=",delta; write "We denote this delta by the shortform"$ shortformdelta:={xi(3,1),xi(3,2),SS,xi(5,1),xi(5,3),SS,xi(6,2),xi(6,3)}$ paramindexeslist:={{3,1},{3,2},{5,1},{5,3},{6,2},{6,3}}$ write "shortformdelta:=", shortformdelta$ %bye$ off nat$ Matrix deltaprime(6,6)$ deltaprime:=phi*delta*phi**(-1)$ write "deltaprime:=phi*delta*phi**(-1)"$ shortformdeltaprime:= for each U in shortformdelta collect if U = ss then U else deltaprime(part(U,1),part(U,2))$ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %case under consideration here for reduction by automorphism write "******* Suppose xi(3,1) = 0 and xi(3,2) = 0 and xi(5,3)=0"$ xi(3,1):=0$ xi(3,2):=0$ xi(5,3):=0$ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% write "phi*delta*phi**(-1):=",phi*delta*phi**(-1); for each U in paramindexeslist do <