 In 1946 , at the recommendation of Navy colleague Donald Howard Menzel , Gleason was appointed a Junior Fellow at Harvard . An early goal of the Junior Fellows program was to allow young scholars showing extraordinary promise to sidestep the lengthy PhD process ; four years later Harvard appointed Gleason an assistant professor of mathematics , though he was almost immediately recalled to Washington for cryptographic work related to the Korean War . He returned to Harvard in the fall of 1952 , and soon after published the most important of his results on Hilbert 's fifth problem ( see below ) . Harvard awarded him tenure the following year . 
