fˈɔːɹmɚli ɐ fˈɪzɪks pɹəfˈɛsɚɹ æt bɹˈændeɪz jˌuːnɪvˈɜːsᵻɾi, klˈeɪtmən wʌz ɛŋkˈɜːɹɪdʒd baɪ pˈɔːl ˈɜːdoʊz tə tʃˈeɪndʒ hɪz fˈiːld ʌv stˈʌdi tə mˌæθɪmˈæɾɪks.
Formerly a physics professor at Brandeis University, Kleitman was encouraged by Paul Erdős to change his field of study to mathematics.