Maximal dilatation
= Maximal dilatation
{title2=$K(f)=\frac{1+\|\mu_f\|_\infty}{1-\|\mu_f\|_\infty}$}
The essential supremum of the ratio of the largest to the smallest infinitesimal <singular value> of a <quasiconformal map>. It equals $(1+\|\mu_f\|_\infty)/(1-\|\mu_f\|_\infty)$ in terms of the <Beltrami coefficient>.