 After the Japanese attacked Pearl Harbor during his senior year , Gleason applied for a commission in the US Navy , and on graduation joined the team working to break Japanese naval codes . ( Others on this team included his future collaborator Robert E. Greenwood and Yale professor Marshall Hall , Jr . ) He also collaborated with British researchers attacking the German Enigma cipher ; Alan Turing , who spent substantial time with Gleason while visiting Washington , called him " the brilliant young Yale graduate mathematician " in a report of his visit . 
