premise: Mikhail Prokhorov is the former chairman of Russia's largest silver producer.
hypothesis: Mikhail Dmitrievitch Prokhorov ( [ Михаи́л Дми́триевич Про́хоров , p = mʲɪxɐˈil ˈdmʲitrʲɪjɪvʲɪtɕ ˈproxərəf ] born 3 May 1965 ) is a Russian billionaire , politician , and owner of the American basketball team the Brooklyn Nets . He is the former chairman of Polyus Gold , Russia 's largest gold producer , and the former President of Onexim Group .