Eisenstein norm
= Eisenstein norm
{c}
{title2=$N(a+b\omega)=a^2-ab+b^2$}
The product of an <Eisenstein integer> $a+b\omega$ and its <complex conjugate>, where $\omega^2+\omega+1=0$. It is multiplicative and converts multiplication into composition identities for the quadratic form $a^2-ab+b^2$.