Seminars and Colloquiums
for the week of January 28, 2008
Speakers:
Professor Xia Chen, Monday
Professor Tobias Lamm, Monday
Professor Junfang Li, Tuesday
Professor David Anderson, Wednesday
Professor Ken Stephenson, Wednesday
Professor Eunok Jung, Thursday
Professor Jeremy Wong , Friday
Monday, January 28
PROBABILITY SEMINAR
TIME: 10:10 – 11:00 a.m.
ROOM: Ayres 309A
SPEAKER: Professor Xia Chen
TITLE: “Limit Laws For The Energy Of A Charge Polymer”
ABSTRACT: In the physics literature, the geometric shape of certain polymers is often modeled by an interpolation line segment with the vertice given as the n-step lattice (simple) random walk. Place a random electric charge – 1 or 1 to each of n vertice of the polymer and suppose that the random charges forms an i.i.d. sequence independent of the polymer. Assume that when two charges meet, the pair with opposite sign gives negative contribution while the pair with same sign gives positive contribution. In this talk, I will speak on some recent progress on the limit laws for the total charges of the polymer generated in this way of interaction.
DIFFERENTIAL GEOMETRY COLLOQUIUM
TIME: 3:35 – 4:25 p.m.
ROOM: Ayres 214
SPEAKER: Professor Tobias Lamm
TITLE: “Approximation of geometric variational problems”
ABSTRACT: Abstract: In this talk I will report on recent results on the approximation of harmonic maps and Willmore surfaces. In particular I will sketch the proof of the energy identity for min-max sequences of the Sacks-Uhlenbeck approximation of harmonic maps and I will outline a new proof showing the existence of a minimizing Willmore torus (the latter is joint work in progress with Ernst Kuwert and Yuxiang Li).
Tuesday, January 29
DIFFERENTIAL GEOMETRY COLLOQUIUM
TIME: 3:40 – 4:30 p.m.
ROOM: Ayres 214
SPEAKER: Professor Junfang Li
TITLE: “Ricci Flow, generalized Inverse Mean Curvature Flow, and monotonicity formulas”
ABSTRACT: In this talk, we will give a brief introduction to Hamilton's Ricci flow equations. The main focus will be on monotonicity formulas of geometric constants appeared in the study of Ricci flow. As applications, some classification results for special solutions of Ricci flow equations will be presented. We will also be interested in extrinsic curvature evolution equations. In this setting, we also found some geometric quantities which are monotonic along an inverse Mean Curvature type of flow. An immediate application is we give a proof to the isoperimetric inequality for Quermassintegrals on some non-convex domains.
Wednesday, January 30, 2008
ALGEBRA SEMINAR
TIME: 3:35 – 4:25 p.m.
ROOM: Ayres 209A
SPEAKER: Professor David Anderson
TITLE: “Filters, ultrafilters, and ultraproducts in ring theory”
ANALYSIS SEMINAR
TIME: 3:35 – 4:25 p.m.
ROOM: Ayres 209A
SPEAKER: Professor Ken Stephenson
TITLE: “Curvature Flows for Discrete Analytic Functions”
ABSTRACT: In studying discrete analytic functions, a "flow" in the computations was observed in work by Chuck Collins, Toby Driscoll, and me. We found that this seemed to represent the discrete analogue of the gradient flow for log(f') in the classical setting. In this talk I'll describe this flow, illustrate the manipulative power it gives us in handling discrete analytic functions, and pose some questions it raises in the classical setting.
Thursday, January 31
SIAM Chapter and Applied Math Seminar
TIME: 3:40 p.m.
ROOM: Ayres 214
SPEAKER: Eunok Jung, Konkuk University, S. Korea
TITLE: “Mathematical Models of Valveless Pumping”
Friday, February 1, 2008
DIFFERENTIAL GEOMETRY COLLOQUIUM
TIME: 3:35 – 4:30 p.m.
ROOM: Ayres 214
SPEAKER: Professor Jeremy Wong
TITLE: “Fibering Manifolds-with-boundary”
ABSTRACT: It is important to know not only how a singularity may appear in a limit of smooth spaces, but also conversely, starting from a sequence of singular spaces, how singularities may disappear. We will discuss the case of manifolds-with-boundary, under certain curvature bounds, that converge to a weakly geodesically extendible space. The topological result is a locally trivial fiber bundle structure. Two main techniques are involved in the proof.
One is a gluing result producing an Alexandrov space. Another is a certain metric analogue of the second-fundamental form of the boundary expressed in terms of distance functions.
Interested in giving or arranging a talk? Check out our calendar.
Previous Announcements:
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Seminars from 2006-2007 academic year