>>609 (2)
>>612 (2)

　[x，y，z] [x，z，y] [S2，t，t]
　|z，x，y| |y，x，z| = |t，S2，t|
　[y，z，x] [z，y，x] [t，t，S2]
の行列式は
　D(x,y,z)^2 = D(S2,t,t).
ここに
　D(x,y,z) = x^3 + y^3 + z^3 -3xyz
　= (x+y+z)(xx+yy+zz-xy-yz-zx)
　= (x+y+z)(S2-t).