## Past Events at the University of British Columbia

### Past Events

- 18-Dec-06

Volume, twist number, and the Jones polynomial of hyperbolic knots

I will describe a few results that relate combinatorial data about a knot or link projection to geometric and topological information about the link complement. For a large family of knots and links, one single piece of diagrammatic data (the twis more››

Scientific Event

- 12-Dec-06

Self-avoiding walk enumeration via the lace expansion

We introduce a new method for the enumeration of self-avoiding walks based on the lace expansion combined with another algorithmic improvement which we call the two step method. We have been able to significantly extend series for the simple cubic more››

Scientific Event

- 12-Dec-06

Drift diffusion equations with fractional diffusion and the quasi-geostrophic equation

The critical dissipative quasi-geostrophic equation was proposed by several authors as a toy model to study the regularity of solutions to 3D Navier-Stokes equations. In this work, in collaboration with L. Caffarelli, we prove that drift-diffusion more››

Scientific Event

- 6-Dec-06

Introduction to Brownian snakes

Discrete models for an evolving population -such as branching random walks- arise in a variety of different contexts. In such models, individuals undergo both a branching phenomenon and a spatial displacement. Superprocesses are obtained as the we more››

Scientific Event

- 6-Dec-06

Homotopical group theory II: p-local finite groups

Scientific Event

- 5-Dec-06

New constructions of volume-critical submanifolds of the sphere

Constant mean curvature hypersurfaces in S^n are critical points of the (n-1)-volume functional subject to an enclosed-volume constraint whereas contact-stationary Legendrian (CSL) submanifolds of S^{2n+1} are n-dimensional submanifolds tangent to more››

Scientific Event

- 5-Dec-06

Remarks on split graphs and related notions

A graph is split if its vertices can be covered by two sets A and B where A induces a complete graph and B induces an empty graph. This concept has many related notions. For example, the number of non-isomorphic set covers of a set of order n is t more››

Scientific Event

- 5-Dec-06

An alternative formulation for a delayed logistic equation

After a brief review of the history and dynamics of the classical logistic and delayed logistic equation models, an alternative expression for a delayed logistic equation is derived assuming that the rate of change of the population depends on thr more››

Scientific Event

- 4-Dec-06

See http://www.math.ubc.ca/~holroyd/sort for pictures. Joint work with Omer Angel, Dan Romik and Balint Virag. Sorting a list of items is perhaps the most celebrated problem in computer science. If one must do this by s more››

Scientific Event

- 4-Dec-06

Plagued by numbers: the mathematics of disease

The dynamics of disease have long fascinated mathematical researchers. From influenza to the bubonic plague, mathematical and computational models are used to evaluate factors governing disease outbreaks. Facts about a disease are put into models. more››

Scientific Event

- 1-Dec-06

High dimensional convex bodies: phenomena, intuitions and results

Phenomena in large dimensions appear in a number of fields of mathematics and related fields of science, dealing with functions of infinitely growing number of variables and with objects that are determined by infinitely growing number of paramete more››

Scientific Event

- 30-Nov-06

Mathematical models in radiation biology

In this talk, I will review concepts in radiation biology that allow us to model the effectiveness of radiation therapy in the treatment of cancer. In particular, I will focus on the Tumour Control Probability (TCP), which is the probability that more››

Scientific Event

- 30-Nov-06

The action on a tree associated to an ideal point of the character variety

Let G be the fundamental group of a compact, orientable, irreducible 3-manifold M. I will discuss the correspondence between ideal points of a curve in the character variety X(G) and actions of G on a tree (following Culler-Shalen). This is a part more››

Scientific Event

- 29-Nov-06

Homotopical group theory I: p-compact groups

Scientific Event

- 29-Nov-06

Hydrodynamic limits of spatially structured coalescents

We are motivated by a question arising in population genetics, and try to describe the effect of migratory fluxes and spatial structure on the genealogy of a population. This leads to the study of systems particles performing simple random walk on more››

Scientific Event

- 28-Nov-06

Oscillatory integral operators mapping $L^2(mathbb R^{n_1})$ to $L^2(mathbb R^{n_2})$ play an important role in many problems in harmonic analysis and partial differential equations. We will briefly discuss the applicability of these operators in more››

Scientific Event

- 28-Nov-06

Puzzles, Tableaux, and Mosaics

The Littlewood-Richardson numbers show up in a number of different areas of mathematics. They are structure constants of the ring of symmetric functions, which connects them to representation theory and cohomology of Grassmannians. There are now s more››

Scientific Event

- 27-Nov-06

The Rotor-router model and Diaconis-Fulton Addition

Given two sets A and B in the lattice, the Diaconis-Fulton sum is a random set obtained by putting one particle in every point of the symmetric difference, and two particles in every point of the intersection, of A and B. Each 'extra particle' per more››

Scientific Event

- 27-Nov-06

Computation of plurigenera of a canonical threefold

For a canonical threefold, there are few known results about plurigenera. We know that a sufficient multiple of canonical divisor generates a nontrivial linear system and that there is a universal multiple. In this talk, we are going to introduce more››

Scientific Event

- 27-Nov-06

For making genetic networks operate robustly, unintelligent non-design suffices

Five years ago we (George von Dassow, Ed Munro, Eli Meir, and Garrett Odell) made mathematical/computer models of two ancient and famous genetic networks that act early in diverse embryos to establish spatial gene expression patterns prefiguring t more››

Scientific Event