Title: The Cauchy transform that vanishes outside a compact.
Abstract: The Cauchy transform of a complex finite compactly supported measure on the plane is its convolution with the Cauchy kernel.
The classical F. and M. Riesz theorem asserts that if the Cauchy transform of a measure $\mu$ on the unit circle
vanishes off the closed unit disk then $\mu$ is absolutely continuous w.r.t. the arc measure on the unit circle.
Motivated by an application in holomorphic dynamics we present a certain generalization of this Riesz theorem
to compact sets whose interior components are finitely connected.