Were Pavel Urysohn and Leonid Levin known for the same type of work?
Leonid Levin: Leonid Anatolievich Levin ( ; Russian: Леони́д Анато́льевич Ле́вин ; Ukrainian: Леоні́д Анато́лійович Ле́він ; born November 2, 1948) is a Soviet-American computer scientist.
i don't know