Michael Handel is an American mathematician known for his work in Geometric group theory.
[1] He received his Ph.D. from University of California, Berkeley, in 1975 under the supervision of Robion Kirby.
[4] Handel was a visiting scholar at the Institute for Advanced Study from 1978 to 1979, and again from 1987 to 1988.
Handel is best known for developing the Train track map method in Geometric group theory in collaboration with Mladen Bestvina in 1992.
[6] Bestvina, Feighn and Handel later proved that the group Out(Fn) satisfies the Tits alternative, settling a long-standing open problem.