## Past Events at the University of British Columbia

### Past Events

- 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

- 27-Sep-06
- 30-Sep-06

Bridging the scales of disease dynamics 2006

The ongoing HIV pandemic, the brief SARS epidemic of 2003 and recurrent fears of a serious influenza outbreak have raised public consciousness of issues surrounding the behaviour and evolution of infectious diseases as they spread through a p more››

Scientific Event

- 27-Sep-06
- 28-Sep-06

Probability of hitting a far point for the voter model

We consider a voter model on the integer lattice started with a single one at the origin. In dimensions 2 and 3, we establish the precise asymptotic behaviour of the probability for the voter model to hit a distant point. We use the scaling limit more››

Scientific Event

- 25-Sep-06

Primitivity in twisted homogeneous coordinate rings

Given a projective k-scheme X, an automorphism sigma of X and an invertible sheaf L on X, one can form the twisted homogeneous coordinate ring bigoplus_{nge 0} H0(X,L_n), where L_n=Lotimes L^{sigma}otimes cdotsotimes L^{sigma^{n-1}. We study the q more››

Scientific Event

- 21-Sep-06

Mathematical Analysis of the Neural Control of Hormone Secretion

The pituitary is one of the primary glands of the body. Many hormones are released from a variety of cells within the pituitary, and these hormones regulate the release of hormones from other glands and have direct actions on the brain, muscles, a more››

Scientific Event

- 19-Sep-06

Comparing sumsets and difference sets

Since addition is commutative but subtraction is not, the subset S+S of a finite set S is predisposed to be smaller than the difference set S-S. As Mel Nathanson wrote: Even though there exist sets S that have more sums than differen more››

Scientific Event

- 18-Sep-06

A Mirror Theorem for Complete Intersection Orbifolds in Weighted Projective Spaces

The famous mirror formula for quintic threefolds, conjectured to Candelas, de la Ossa, Green, and Parkes, provides detail information on genus zero Gromov-Witten invariants of the quintic threefold. Mirror formula has been extended to larger class more››

Scientific Event

- 14-Sep-06

Closed form solution for maximizing CRRA type utility

This paper studies the problem of optimal investment in incomplete markets when the agents have CRRA type utility. Closed form solutions are obtained up to some unhedgeble risk represented by a process orthogonal on the stock price. The more››

Scientific Event

- 14-Sep-06

On classifications of links up to C_n-moves

A C_n-move (nin{Bbb N}) is a local move on links defined by Habiro, which can be regarded as a 'higher order crossing change'. The C_n-equivalence is an equivalence relation on links generated by C_n-move. The C_m-equivalence implies the C_n-equiv more››

Scientific Event

- 14-Sep-06

Arthur Sherman (Laboratory of Biological Modeling, NIDDK/NIH)

Scientific Event