Joel Hass is an American mathematician and a professor of mathematics and at the

University of California, Davis The University of California, Davis (UC Davis, UCD, or Davis) is a Public university, public Land-grant university, land-grant research university in Davis, California, United States. It is the northernmost of the ten campuses of the University ...

.Faculty profile
an
math department contact information
UC Davis, retrieved 2012-07-03. His work focuses on geometric and topological problems in dimension 3.

Biography

Hass received his Ph.D. from the

University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a Public university, public Land-grant university, land-grant research university in Berkeley, California, United States. Founded in 1868 and named after t ...

in 1981 under the supervision of

Robion Kirby Robion Cromwell Kirby (born February 25, 1938) is a Professor of Mathematics at the University of California, Berkeley who specializes in low-dimensional topology. Together with Laurent C. Siebenmann he developed the Kirby–Siebenmann invariant ...

. He joined the Davis faculty in 1988. In 2012 he became a fellow of the

American Mathematical Society The American Mathematical Society (AMS) is an association of professional mathematicians dedicated to the interests of mathematical research and scholarship, and serves the national and international community through its publications, meetings, ...

. 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 In mathematics, the unknotting problem is the problem of algorithmically recognizing the unknot, given some representation of a knot, e.g., a knot diagram. There are several types of unknotting algorithms. A major unresolved challenge is to de ...

is in NP, and for giving an exponential bound on the number of

Reidemeister move In the mathematical area of knot theory, a Reidemeister move is any of three local moves on a link diagram. and, independently, , demonstrated that two knot diagrams belonging to the same knot, up to planar isotopy, can be related by a seque ...

s needed to reduce the

unknot In the knot theory, mathematical theory of knots, the unknot, not knot, or trivial knot, is the least knotted of all knots. Intuitively, the unknot is a closed loop of rope without a Knot (mathematics), knot tied into it, unknotted. To a knot ...

to a circle.

Selected publications

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

References

External links

Home page at UC DavisGoogle scholar profile
{{DEFAULTSORT:Hass, Joel Year of birth missing (living people) Living people 20th-century American mathematicians University of California, Berkeley alumni University of California, Davis faculty Fellows of the American Mathematical Society American topologists 21st-century American mathematicians