## Past Events at the University of British Columbia

### Past Events

- 23-Oct-06

The quantum McKay correspondence in dimension two

Let G be a finite subgroup of SU(2). The classical McKay correspondence describes the cohomology ring of Y the minimal resolution of C2/G in terms of the representation theory of G. We give a description of the quantum cohomology of Y in terms of more››

Scientific Event

- 23-Oct-06

Wild fish, farmed fish and sea lice—a big-box model with spatial effects

The Anderson-May dynamical model for host-macroparasite systems is extended to include resource limitation and the distribution of both resource limitation effects and parasite pathogenicity over host mortality and natality. When the equilibrium h more››

Scientific Event

- 19-Oct-06

Fluid Mathematical Models of Traffic Flow

I will start with a few basic facts on other types of description (microscopic, kinetic ...) Then I will talk about fluid models, of 'first order': Lighthill-Whitham-Richards (LWR) , i.e. a scalar conservation law, robust and (too ?) simple. The f more››

Scientific Event

- 19-Oct-06

Impact of Travel Between Patches for Spatial Spread of Disease

A patch model is proposed to study the impact of travel on the spatial spread of disease between patches. The basic reproduction number for the i-th patch in isolation, is obtained along with the basic reproduction number of the system, $mathcal{R more››

Scientific Event

- 18-Oct-06

Arithmetic Fuchsian groups of genus two

A hyperbolic 2- or 3-orbifold M is called arithmetic if M = H^2/G or H^3/G where G is an arithmetic Fuchsian or Kleinian group, respectively. Considerable work has been done in the last two decades classifying these groups. I will explain how arit more››

Scientific Event

- 16-Oct-06

Frozen boundaries and log-fronts

In this talk, based on a joint work with Richard Kenyon and Grisha Mikhalkin, Andrei Okounkov will discuss some simple binary operation on plane curves which 1) generalizes classical duality for plane curves, 2) arises naturally in probabilistic c more››

Scientific Event

- 16-Oct-06

Integral cohomology of singular toric varieties

The singular cohomology and Chow cohomology, with Q-coefficients, of projective toric varieties with at worst orbifold singularities are well-understood, but interesting problems remain for toric varieties with more serious singularities and for c more››

Scientific Event

- 12-Oct-06

Implicit Immersed Boundary Methods with Boundary Mass

The immersed boundary method is a general framework used to handle fluid-structure interactions. One computational bottleneck of the immersed boundary methods is that the elastic structures are often very stiff, necessitating the use of a very fin more››

Scientific Event

- 12-Oct-06
- 16-Oct-06

Frontiers in Biophysics: Modelling and Experiment.

Frontiers in Biophysics: Modelling and Experiment is a weekend retreat that is being organized by graduate students and faculty in biophysics and mathematical biology at Simon Fraser University and the University of British Columbia. This event is more››

Scientific Event

- 11-Oct-06

Effect of noise on front propagation in KPP equations

We study random traveling waves in KPP equations with appropriate additive noise. We prove a very explicit conjecture of Brunet and Derrida concerning the dramatic slowdown of these fronts by the noise. This is joint work with Carl Mueller and Leo more››

Scientific Event

- 11-Oct-06

Khovanov's construction of a homology theory for knots allows us to view the Jones polynomial as an Euler characteristic, provides a stronger knot invariant, and is the main tool for Rasmussen's combinatorial proof of the Milnor conjecture. In thi more››

Scientific Event

- 11-Oct-06

The 290-Theorem and Representing Numbers by Quadratic Forms

This talk will describe several finiteness theorems for quadratic forms, and progress on the question: "Which positive definite integer-valued quadratic forms represent all positive integers?". The answer to this question depends on sett more››

Scientific Event

- 10-Oct-06

Three challenges of Claude Shannon

In 1948/1949 Claude Shannon wrote two papers~[Sha48,Sha49] which became the foundation of modern information theory. The papers showed that information can be compressed up to the `entropy', that data can be transmitted error free at a rate below more››

Scientific Event

- 10-Oct-06

Common Agency with Informed Principals: an Economics Lecture

The provision of public goods under asymmetric information has generally been viewed as a mechanism design problem under the aegis of an uninformed mediator. This paper focuses on institutional contexts where no such mediator is available. Contrib more››

Scientific Event

- 10-Oct-06

Regularity criteria for Navier-Stokes equations

In the talk I will first review various known regularity criteria and partial regularity theory for 3D incompressible Navier-Stokes equations. I will then talk about a joint work with Gustafson and Kang on regularity criteria based on scaled space more››

Scientific Event

- 5-Oct-06

Functional equations for Mahler measures of genus-one curves

The Mahler measure of an n -variable polynomial P is the integral of log | P | over the n -dimensional unit torus T n with the Haar measure. Consider a family of two-variable polynomials whose coefficients depend on one parameter. Then the Mahler mea more››

Scientific Event

- 3-Oct-06

Semilinear elliptic systems with exponential nonlinearities in two dimensions

We study the existence of nontrivial solutions for the following system of two coupled semilinear Poisson equations: left{ begin{array}{rlllllll} -Delta u &=& g(v), & v & > & 0 & extrm{in} Ω, \ -Delta v &=& more››

Scientific Event

- 3-Oct-06

Numerical schemes for ordinary differential equations, using matrix exponentials, were introduced in the 1960's as a way to overcome the stability restrictions of explicit methods. However, such methods were not considered as a practical mean of s more››

Scientific Event

- 2-Oct-06

Ehrhart analogue of the h-polynomial

In this talk I will explain how the Ehrhart problem of counting lattice points in a polyhedron is equivalent to a problem in orbifold cohomology. This equivalence can be used to prove a conjecture of Stanley that relates the Ehrhart generating pol more››

Scientific Event

- 28-Sep-06

Perturbations Methods in Default Modeling

Stochastic volatility has played a central role in modeling equity derivative markets. In the recent years the market in credit-linked derivative products has grown tremendously and had generated a need for more sophisticated models of default. We more››

Scientific Event