Southeast Geometry Seminar

SGS XXIV: Sunday, March 30, 2014, Georgia Institute of Technology

The Southeast Geometry Seminar (SGS) is a semiannual series of one day event sponsored by:

The organizers are: Vladimir Oliker (Emory), Mohammad Ghomi and John McCuan (Georgia Tech), Fernando Schwartz (UTK), Junfang Li (UAB), and Gilbert Weinstein (previoulsy with UAB).

Thanks to an NSF grant, we have funds to support participants, particularly students and recent Ph.D. recipients. We encourage women and minorities to apply. To apply please write to us.

Location: All talks will be held at

005 Skiles Building

8:45AM - 9:25AM - Refreshments and poster session 005 Skiles Building

9:25AM Announcements

Morning Session

9:30AM - Xiangwen Zhang (Columbia University)

Abstract: A classical uniqueness theorem of Alexandrov says that: a closed strictly convex twice differentiable surface in R3 is uniquely determined to within a parallel translation when one gives a proper function of the principle curvatures. We will talk about a new PDE proof for this thorem by using the maximal principle and weak uniqueness continuation theorem of Bers-Nirenberg. More generally, we prove a version of this theorem with the minimal regularity assumption: the spherical hessians of the supporting functions for the corresponding convex bodies as Radon measures are nonsingular. This is a joint work with P. Guan and Z. Wang.

10:30AM - Bo Guan (Ohio State University)
The concavity and subsolutions in estimates for fully nonlinear elliptic equations on manifolds

Abstract: We report recent progresses in our effort of seeking methods to derive a priori second order estimates for fully nonlinear elliptic (and parabolic) equations on real or complex manifolds under general structure conditions. We are concerned with both equations on closed manifolds, and the Dirichlet problem on manifolds with boundary without imposing geometric restrictions to the boundary except being smooth and compact. In particular, our existence results are essentially optimal for domains in real or complex Euclidean space (or manifolds with nonnegative curvature). In this talk we'll discuss the role of concavity and subsolution.

11:30AM - Robert Finn (Stanford University)
Partly immersed balls in a weightless environment

12:30AM - 2:15PM - Lunch

Afternoon Session

2:30PM - Fernando Schwartz (University of Tennessee)
Computational Geometry and Topology

Abstract: I will present some problems in data analysis that can be attacked using tools inspired by topology and geometry, and will show many pictures.

3:30PM - John Harvey (Notre Dame)
Orbifolds and Alexandrov geometry

Abstract: Perelman's celebrated stability theorem showed that if a convergent sequence of Alexandrov spaces does not drop in dimension on passing to the limit, then the objects in the tail of the sequence are homeomorphic to the limit.
In this talk, the theorem will be extended to an equivariant setting. As an application, it will be shown that two classes of Riemannian orbifolds, defined by geometric and spectral constraints, are finite up to orbifold homeomorphism.

4:30PM - Henry C. Wente (The University of Toledo)
Bifurcation and symmetry-breaking for liquids in grooved channels

Abstract: Consider a liquid in contact with a solid. In equilibrium the free surface will have constant mean curvature and be subject to the volume constraint. We focus on easily visualized examples where there is a symmetry-breaking bifurcation at a critical juncture with a loss of stability as volume is increased. We follow the bifurcating family.

Authored by:

Junfang Li and Gilbert Weinstein
Last Modified on: