Polynomial length
= Polynomial length
{title2=$\mathcal L(P)$}
For a polynomial $P=\sum_{\mathbf i}a_{\mathbf i}\mathbf X^{\mathbf i}$, its length is the sum of the absolute values of its coefficients:
$$
\mathcal L(P)=\sum_{\mathbf i}|a_{\mathbf i}|.
$$