In this talk, using the local Ricci flow, we prove the short-time
existence of the Ricci flow on noncompact manifolds, whose Ricci curvature
has global lower bound and sectional curvature has only local average integral
bound. The short-time existence of the Ricci flow on noncompact manifolds
was studied by Wan-Xiong Shi in 1990s, who required a point-wise bound of
curvature tensors. As a corollary of our main theorem, we get the short-time existence part of Shis theorem in this more general context.
In this talk by using the idea in the proof of Perelman's pseudo locality theorem we will derive a local curvature bound in Ricci flow assuming only local sectional curvature bound and local volume lower bound for the initial metric.
This result is closely related to Theorem 10.3 in Perelman's entropy paper.
This Friday will be mandatory only for graduate students who have been a TA for strictly less than two quarters. (ie. If you were a TA for two quarters or more last year or over the summer, you do not have to come this week!) This week we will be discussing several first week of class issues including: WebWorks, the Tutoring Center, and Dealing with Difficult Classroom Situations.
* Workshop for Undergraduate Students on preparing for and applying to graduate school. All levels of students are encouraged to attend. The workshop will feature a presentation on what students should do in their Sophomore-Senior years to prepare for graduate studies and how to apply for graduate school. Also, there will be a panel of current UCI students to offer advice on the application process and selecting a school.
The one dimensional quantum Ising model is used in quantum statistical physics to model interracting particles on a discrete lattice. While the classical model (in one and two dimensions) has long been solved (its origin dates back to 1930's), its quasiperiodic analog (dating back about 25 years) is still a source of interesting problems. We shall discuss our solution to one such problem: we'll rigorously prove that the energy spectrum of the one dimensional quantum quasiperiodic Ising model is a Cantor set, as has been long believed, and discuss some of its properties.
This is the first in a series of two seminars dedicated to this topic. In this seminar we'll present the problem and set up the main ideas.
In 1970s S.Newhouse discovered that a generic homoclinic bifurcation of a smooth surface diffeomorphism leads to persistent homoclinic tangencies, infinite number of attractors (or repellers), and other unexpected dynamical properties (nowadays called "Newhouse phenomena"). More than 20 years later P.Duarte provided an analog of these results in conservative setting (with attractors replaced by elliptic periodic points). We will discuss these and other recent results on conservative homoclinic bifurcations, and list some related open problems in the field.
A survey of automatic continuity in Banach algebras with a focus on the case of a derivation on a Banach Jordan triple. (Joint work with Antonio Peralta)