Equation 14.29.16C72BCF7334A2

\begin{equation} \operatorname {Vol}\{ f_*\leq s\} \asymp \sqrt s\quad (s\downarrow 0), \qquad f_*^{-\alpha }\in L^1\quad \Longleftrightarrow \quad \alpha <\tfrac 12. \end{equation}