Joel Hass

Joel Hass at Berkeley in 1987

Joel Hass is an American mathematician and a professor of mathematics and at the University of California, Davis.[1] 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.[2] He joined the Davis faculty in 1988.[1]

In 2012 he became a fellow of the American Mathematical Society.[3] From 2010 to 2014 he served as the chair of the UC Davis mathematics department.[4]

Research contributions

Hass is known for proving the equal-volume special case of the double bubble conjecture,[5] for proving that the unknotting problem is in NP,[6] and for giving an exponential bound on the number of Reidemeister moves needed to reduce the unknot to a circle.[7]

Selected publications

Research papers
  • Freedman, Michael; Hass, Joel; Scott, Peter (1983), "Least area incompressible surfaces in 3-manifolds" (PDF), Inventiones Mathematicae, 71 (3): 609–642, Bibcode:1983InMat..71..609F, doi:10.1007/BF02095997, hdl:2027.42/46610, MR 0695910, S2CID 42502819.
  • Hass, Joel; Lagarias, Jeffrey C.; Pippenger, Nicholas (1999), "The computational complexity of knot and link problems", Journal of the ACM, 46 (2): 185–211, arXiv:math/9807016, doi:10.1145/301970.301971, S2CID 125854.
  • Hass, Joel; Schlafly, Roger (2000), "Double bubbles minimize", Annals of Mathematics, Second Series, 151 (2): 459–515, arXiv:math/0003157, Bibcode:2000math......3157H, doi:10.2307/121042, JSTOR 121042, MR 1765704, S2CID 15663910.
  • Hass, Joel; Lagarias, Jeffrey C. (2001), "The number of Reidemeister moves needed for unknotting", Journal of the American Mathematical Society, 14 (2): 399–428, arXiv:math/9807012, doi:10.1090/S0894-0347-01-00358-7, MR 1815217, S2CID 15654705.
Books

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

References

  1. ^ a b Faculty profile and math department contact information, UC Davis, retrieved 2012-07-03.
  2. ^ Joel Hass at the Mathematics Genealogy Project
  3. ^ List of Fellows of the American Mathematical Society, retrieved 2013-01-19.
  4. ^ "Editorial and other Service". www.math.ucdavis.edu. Retrieved 2021-11-16.
  5. ^ Hass & Schlafly (2000).
  6. ^ Hass, Lagarias & Pippenger (1999).
  7. ^ Hass & Lagarias (2001).