Seminars and Colloquia by Series

Series: PDE Seminar
Wednesday, December 13, 2017 - 15:00 , Location: Skiles 005 , Mahir Hadžić , King's College London , , Organizer: Yao Yao
In a recent work Sideris constructed a finite-parameter family of compactly supported affine solutions to the free boundary compressible Euler equations satisfying the physical vacuum condition.  The support of these solutions expands at a linear rate in time. We show that if the adiabatic exponent gamma belongs to the interval(1, 5/3] then these affine motions are globally-in-time nonlinearly stable. If time permits we shall also discuss several classes of global solutions to the compressible Euler-Poisson system. This is a joint work with Juhi Jang.
Friday, December 8, 2017 - 15:00 , Location: Skiles 005 , Matthew Yancey , Inst. for Defense Analysis , Organizer: Lutz Warnke
Wednesday, December 6, 2017 - 12:10 , Location: Skiles 006 , John Etnyre , GT Math , Organizer:
Wednesday, December 6, 2017 - 11:15 , Location: Skiles 005 , Kelly Yancey , Institute for Defense Analyses , , Organizer: Michael Damron
Monday, December 4, 2017 - 14:00 , Location: Skiles 006 , Soren Galatius , Stanford University , Organizer: Kirsten Wickelgren
Monday, December 4, 2017 - 13:55 , Location: Skiles 005 , Prof. Tao Pang , Department of Mathematics, North Carolina State University , , Organizer: Molei Tao
In the real world, the historical performance of a stock may have impacts on its dynamics and this suggests us to consider models with delays. We consider a portfolio optimization problem of Merton’s type in which the risky asset is described by a stochastic delay model. We derive the Hamilton-Jacobi-Bellman (HJB) equation, which turns out to be a nonlinear degenerate partial differential equation of the elliptic type. Despite the challenge caused by the nonlinearity and the degeneration, we establish the existence result and the verification results.
Friday, December 1, 2017 - 15:00 , Location: Skiles 005 , Mustazee Rahman , MIT , , Organizer: Lutz Warnke
Suppose we want to find the largest independent set or maximal cut in a sparse Erdos-Renyi graph, where the average degree is constant. Many algorithms proceed by way of local decision rules, for instance, the "nibbling" procedure. I will explain a form of local algorithms that captures many of these. I will then explain how these fail to find optimal independent sets or cuts once the average degree of the graph gets large. There are some nice connections to entropy and spin glasses.
Friday, December 1, 2017 - 14:00 , Location: Skiles 006 , TBA , GT Math , Organizer: Sung Ha Kang
Thursday, November 30, 2017 - 15:05 , Location: Skiles 006 , Matthew Junge , Duke University , , Organizer: Gerandy Brito
Cars are placed with density p on the lattice. The remaining vertices are parking spots that can fit one car. Cars then drive around at random until finding a parking spot. We study the effect of p on the availability of parking spots and observe some intriguing behavior at criticality. Joint work with Michael Damron, Janko Gravner, Hanbeck Lyu, and David Sivakoff. arXiv id: 1710.10529.
Thursday, November 30, 2017 - 13:30 , Location: Skiles 005 , Shijie Xie , Math, Gt , Organizer: Robin Thomas
Let G be a graph containing 5 different vertices a0, a1, a2, b1 and b2. We say that (G, a0, a1, a2, b1, b2) is feasible if G contains disjoint connected subgraphs G1, G2, such that {a0, a1, a2}⊆V(G1) and {b1, b2}⊆V(G2). In this talk, we will complete a sketch of our arguments for characterizing when (G, a0, a1, a2, b1, b2) is feasible. Joint work with Changong Li, Robin Thomas, and Xingxing Yu.