1921-

American mathematician who in 1952 joined colleagues Deane Montgomery and Leo Zippin in developing a complete solution to Hilbert's Fifth Problem, which considered properties of analytic manifolds. Specifically, Gleason was able to show that any locally compact topological group is a limit of Lie groups, serving to emphasize the importance of Lie groups in the theory of continuous groups. This proved to be the definitive solution to the fifth of 23 problems posed by David Hilbert to the International Mathematical Congress 52 years earlier.