%0 Report %A Mera Rivas, María Eugenia %A Morán Cabré, Manuel %T A zero-one half law for porosity of measures %J Documentos de Trabajo de la Facultad de Ciencias Económicas y Empresariales %D 2000 %@ 2255-5471 %U https://hdl.handle.net/20.500.14352/64137 %X We prove that the upper porosity of any Radon probability measure is either 0 or 1/2 %~