>>645
(x-y)(y-z)
=-{y^2-(z+x)y+zx}
=-{y^2-(σ1-y)y+σ2-y(z+x)}
=-{y^2-(σ1-y)y+σ2-y(σ1-y)}
=-{3y^2-2(σ1)y+σ2}

(x-y)^2(y-z)^2(z-x)^2
={(x-y)(y-z)}{(y-z)(z-x)}{(z-x)(x-y)}
=-{3x^2-2(σ1)x+σ2}{3y^2-2(σ1)y+σ2}{3z^2-2(σ1)z+σ2}

めんどいな・・・・
ええ方法あるかな・・・