Past Events
Scientific, Seminar
DG-MP-PDE Seminar: Nonlinear singular operators and measure data quasilinear Riccati type equations with nonstandard growth
April 6, 2010
University of British Columbia
We establish explicit criteria of solvability for the quasilinear Riccati type equation $-\Delta_p u =|\nabla u|^q + \omega$ in a bounded $\mathcal{C}^1$ domain $\Omega\subset\mathbb{R}^n$, $n\geq 2$. Here $\Delta_p$, $p>1$, is the $p$-Laplacian, $q$...
Scientific, Seminar
PIMS/AMI Seminar: Nonlinear waves in traffic flow
April 6, 2010
University of Alberta
Continuum traffic theories whereby individual vehicles are collectively modeled have enjoyed a rich history since their popularization by M.J. Lighthill and G.B. Whitham. These models are able to elucidate the dynamics of ``phantom jams,'' transient...
Scientific, Seminar
PIMS/WMAX Postdoctoral Colloquium: Weighted Ehrhart theory and orbifold cohomology
April 1, 2010
University of British Columbia
Motivated by geometry, we consider a `less discrete' way of counting lattice points in polytopes, in which one assigns a certain `weight' to each lattice point. On the combinatorial side, this approach reveals some `hidden symmetry' which improves...
Scientific, Seminar
Topology Seminar: In pursuit of DeRham cohomology for E_{\infty}-algebras
April 1, 2010
University of British Columbia
We will discuss our motivation for understanding what the analogue of DeRham cohomology should be for E_{\infty}-algebras in connection with algebraic K-theory and topological cyclic homology.
Scientific, Seminar
PIMS/AMI Seminar: Quasi-neutral Limit of the Schrodinger-Poisson System in Coulomb Gauge
April 1, 2010
University of Alberta
The zero Debye length asymptotic of the Schrodinger-Poisson system in Coulomb gauge for ill-prepared initial dada is studied. We prove that the Debye length to the current density defined by the solution of the Schrodinger-Poisson system in Coulomb...
Scientific, Seminar
Topology Seminar: Introduction to Ratner's Theorems on Unipotent Flows
March 31, 2010
University of British Columbia
Let f be the obvious covering map from Euclidean n-space to the n-torus. It is well known that if L is any straight line in n-space, then the closure of f(L) is a very nice submanifold of the n-torus. In 1990, Marina Ratner proved a beautiful...
Scientific, Seminar
Probability Seminar: Continuous-time branching processes to model viral load in treated HIV+ individuals
March 31, 2010
University of British Columbia
We will discuss continuous-time, multi-type branching problems to model aspects of HIV-virus and T-cell dynamics in the blood stream. We are motivated by observations of viral load in HIV+ patients on anti-retroviral treatment (ART). While on ART for...
Scientific, Seminar
Discrete Math Seminar: Gene trees and species trees: parsimony problems
March 30, 2010
University of British Columbia
A gene family is a set of genes, present in the genomes of several genomes, possibly in multiple occurrences in some genomes, that all originates from a single ancestral gene. A gene tree is a binary tree that describes evolutionary relationships...
Scientific, Seminar
Approximating the Solution to a Static Hamilton-Jacobi Equation in a Single Monotone Pass
March 30, 2010
University of British Columbia
In the context of optimal control, the Hamilton-Jacobi Partial Differential Equation (HJ PDE) is a continuous analogue to the discrete Bellman dynamic-programming equation. Both of these equations satisfy a causal property: the solution value at a...
Scientific, Seminar
Regularity of the extremal solution in fourth order problems on general domains
March 30, 2010
University of British Columbia
I will discuss recent results concerning the regularity of the extremal solution associated with fourth order nonlinear eigenvalue problems on general domains. We show that the extremal solution is bounded under various assumptions on the...