# Painleve's problem and the semiadditivity of analytic capacity

Research paper by Xavier Tolsa

Indexed on: 02 Apr '02Published on: 02 Apr '02Published in: Mathematics - Classical Analysis and ODEs

#### Abstract

Let $\gamma(E)$ be the analytic capacity of a compact set $E$ and let $\gamma_+(E)$ be the capacity of $E$ originated by Cauchy transforms of positive measures. In this paper we prove that $\gamma(E)\approx\gamma_+(E)$ with estimates independent of $E$. As a corollary, we characterize removable singularities for bounded analytic functions in terms of curvature of measures, and we deduce that $\gamma$ is semiadditive, which solves a long standing question of Vitushkin.