Past Events
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...
Scientific, Seminar
WENTS Seminar: An equivariant class number formula by more elementary methods
March 26, 2010
University of Calgary
In 2009, Büyükboduk published a result in Crelle which expressed the order of the $\chi$-part of the class-group of a number field ($\chi$ a $p$-adic character of a Galois group) in terms of $L$-functions and regulators. The proof used Kolyvagin...
Scientific, Seminar
PIMS Symplectic Geometry Seminar: Coisotropic submanifolds, deformation, and models for the leaf space of a foliation
March 25, 2010
University of British Columbia
Coisotropic submanifolds of symplectic manifolds are canonically foliated. Their deformation is described by an L-infinity algebra with a known geometric description. I will describe some calculations with the obstruction theory of this L-infinity...
Scientific, Seminar
PIMS Special Seminar: Richard Brualdi (Wisconsin-Madison)
March 25, 2010
University of Victoria
(0,1)-matrices are, in particular, nonnegative matrices, and so the Perron-Frobenius theory of nonnegative matrices applies to them. Thus they have a nonnegative eigenvalue that is at least as large as the magnitude of all other eigenvalues...
Scientific, Seminar
Topology Seminar: Relations amongst motivic Hopf maps
March 24, 2010
University of British Columbia
I will talk about work with Dan Isaksen on the motivic homotopy groups of spheres, focusing on the story of the Hopf maps. In classical algebraic topology the Hopf maps generate a very small and easily computed subring of the stable homotopy ring...