Joel Hass

Joel Hass is an American mathematician and a professor of mathematics and at the University of California, Davis. His work focuses on geometric and topological problems in dimension 3.

Biography
Hass received his Ph.D. from the University of California, Berkeley in 1981 under the supervision of Robion Kirby. He joined the Davis faculty in 1988.

In 2012 he became a fellow of the American Mathematical Society. From 2010 to 2014 he served as the chair of the UC Davis mathematics department.

Research contributions
Hass is known for proving the equal-volume special case of the double bubble conjecture, for proving that the unknotting problem is in NP, and for giving an exponential bound on the number of Reidemeister moves needed to reduce the unknot to a circle.

Selected publications

 * Research papers

2004: Student Solutions Manual, Maurice D. Weir, Joel Hass, George B. Thomas, Frank R Giordano
 * Books