Estimates of the harmonic measure of a continuum in the unit disk
Carl H. Fitzgerald, Burton Rodin, Stefan E. Warschawski · Transactions of the American Mathematical Society · 1985
The harmonic measure of a continuum in the unit disk is estimated from below in two ways. The first estimate is in terms of the angle subtended by the continuum as viewed from the origin. This result is a dual to the Milloux problem. The second estimate is in terms of the diameter of the continuum. This estimate was conjectured earlier as a strengthening of a theorem of D. Gaier. In preparation for the proofs several lemmas are developed. These lemmas describe some properties of the Riemann mapping function of a disk with radial incision onto a disk.