## Scientific Lectures

- 1-Feb-07

Quartic K3 surfaces without nontrivial automorphisms

We will deal with a gap in a result of Bjorn Poonen. He found explicit examples of hypersurfaces of degree d³3 and dimension n³1 over any field, such that the group of automorphisms over the algebraic closure is trivial, except for the pairs (n, more››

University of British Columbia

- 31-Jan-07

Nilpotent commutators and reducibility of semigroups

Let f be a noncommutative polynomial in two variables. Let mathcal{S} be a multiplicative semigroup of linear operators on a finite-dimensional vector space and T a fixed linear operator such that f(T,S)=0 for all S in mathcal{S}. What can w more››

University of British Columbia

- 29-Jan-07

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››

University of British Columbia

- 29-Jan-07

Statistical modeling in setting air quality standards

The earth's atmosphere is a stochastic complex system which includes amongst other things pollution fields some of which derive from anthropogenic sources. Because of their negative health impacts, these fields are now the subject to regulation. H more››

University of Washington

- 26-Jan-07

Sequential Experiment Design for Contour Estimation from Computer Simulators

In many engineering applications, one is interested in identifying the inputs to a computer simulator that lead to a pre-specified output. In this talk we introduce statistical methodology that identifies the desired contour in the input space. Th more››

Simon Fraser University

- 25-Jan-07

Robust Stochastic Discount Factors

When market is incomplete a new non-redundant derivative security cannot be priced by no arbitrage arguments alone. Moreover there will be a multiplicity of stochastic discount factors and each of them may give a different price for the new deriva more››

University of British Columbia

- 25-Jan-07

UBC Mathematics Department Colloquium Hosted by PIMS-UBC 2007

A discrete group has 'Property (T)' if every isometric (affine) action of the group on Hilbert space has a global fixed point. This is a spectral-gap property and was originally defined by Kazhdan to study lattices in Lie groups. Recently Gromov f more››

University of British Columbia

- 24-Jan-07

Long-term evolution of polygenic traits under frequency-dependent intraspecific competition

We analytically investigate the long-term evolution of a continuously varying quantitative character in a diploid population that is determined additively by a finite number of loci. The trait is under a mixture of frequency-dependent disruptive s more››

University of British Columbia

- 23-Jan-07

New singular solutions of the Nonlinear Schrodinger equation (NLS)c

The study of singular solutions of the NLS goes back to the 1960s, with applications in nonlinear optics and, more recently, in BEC. Until recently, the only known singular solutions had a self-similar 'peak-type' profile that approaches a delta f more››

University of British Columbia

- 23-Jan-07

Mirkovic-Vilonen cycles on the affine Grassmannian

The geometric Satake correspondence relates representation theory to the geometry of the affine Grassmannian. In particular, certain subvarieties of the affine Grassmanian, called Mirkovic-Vilonen cycles, give bases for representations of complex more››

University of British Columbia

- 19-Jan-07

A Simple Technique for Solving Partial Differential Equations on Surfaces

Many applications require the solution of time dependent partial differential equations (PDEs) on surfaces or more general manifolds. Methods for treating such problems include surface parameterization, methods on triangulated surfaces and embeddi more››

Simon Fraser University

- 19-Jan-07

One of the most recurrent themes in Geometry, is the study of objects that locally look the same. I will explain, mainly via examples and in non-technical terms, how the concept of 'locally look the same' has evolved through time (mostly through s more››

University of British Columbia

- 18-Jan-07

In this talk I will present two pieces of work in progress. In the first half of the talk I will speak about the evolution of phenotype determining mechanisms. Many heterogeneous environments favour different phenotypes in different places or at d more››

University of British Columbia

- 17-Jan-07

MITACS Math Finance Seminar 2007

We study the existence of a numeraire portfolio for a discrete time financial market with proportional transaction costs. In an incomplete market without frictions, consistent prices for derivative securities can be obtained by taking the expectat more››

University of British Columbia

- 17-Jan-07

Normal subgroups of the braid groups and the Dehornoy ordering

The braid groups admit a left-ordering, known as the Dehornoy ordering, which has come up under many guises in recent years. I will show that normal subgroups interact with the Dehornoy ordering in such a way that 'nearly all' normal subgroups of more››

University of British Columbia

- 16-Jan-07

Cooperation in Social Dilemmas: The Role of Punishment and Volunteering

The emergence and maintenance of cooperative behavior that is beneficial to others but costly to the individual represents a major conundrum in evolutionary biology. Punishment represents an efficient mechanism to stabilize and maintain cooperatio more››

University of British Columbia

- 11-Jan-07

Inflation Indexed Swaps and Swaptions

This article considers the pricing of inflation indexed swaps, inflation indexed swaptions, and options on inflation indexed bonds. To price the inflation indexed swaps, we suggest an extended HJM model. The model allows both the forward rates and more››

University of British Columbia

- 11-Jan-07

Bergman metrics and geodesics in the space of Kahler metrics

The space of positively curved hermitian metrics on a positive holomorphic line bundle over a compact complex manifold is an infinite-dimensional symmetric space. It is shown by Phong and Sturm that geodesics in this space can be uniformly approxi more››

University of British Columbia

- 11-Jan-07

A multiphase flow model of calcium induced morphology changes in true slime mold

The true slime mold Physarum polycephalum is a single cell organism reaching up to meters in size. The cytoplasm shows periodic shuttle streaming through a network of tubular structures attaining velocities up to 1 mm/s. The motion is driven by th more››

University of British Columbia

- 11-Jan-07

On Some of the Differences Between Z and Z^2 in Dynamics

Around 1970 it was discovered that measure preserving actions of Z^2 on probability spaces can have remarkably different properties from Z-actions, i.e. from actions of single transformations. Many of these differences can be described as 'rigidit more››

University of Washington