Abstract:
Let $\nu$ be a (complex) Radon measure in $\mathbb C$ with compact support
and finite variation and let
$$
\mathscr C_*\nu(z)=\sup_{\varepsilon>0}
\biggl|\int_{|\zeta-z|>\varepsilon}\frac{d\nu(\zeta)}{\zeta-z}\biggr|
$$
be the maximal Cauchy integral. Estimates for the Hausdorff
$h$-content of the set
$\mathscr Z^*(\nu,P)=\bigl\{z\in\mathbb C:\mathscr C_*\nu(z)>P\bigr\}$
are obtained, where $h$ is a measuring function and $P$ is a fixed positive number. These estimates are shown to be sharp up to the values of
the absolute constants involved. A similar problem is also considered
for potentials with arbitrary real non-increasing kernels of positive
measure in $\mathbb R^m$, $m\geqslant1$. As an application of the
so-developed machinery, results on connections between the
analytic capacity and the Hausdorff measure are obtained (for
instance, an analogue of Frostman's theorem on classical capacities).
Bibliography: 37 titles.