Scientific

New geometric and functional analytic ideas arising from problems in symplectic geometry

Speaker: 
Helmut Hofer
Date: 
Mon, Oct 23, 2006 to Tue, Oct 24, 2006
Location: 
PIMS, University of British Columbia
Conference: 
PIMS 10th Anniversary Lectures
Abstract: 

The study of moduli spaces of holomorphic curves in symplectic geometry is the key ingredient for the construction of symplectic invariants. These moduli spaces are suitable compactifications of solution spaces of a first order nonlinear Cauchy-Riemann type operator. The solution spaces are usually not compact due to bubbling-off phenomena and other analytical difficulties.

Class: 

Frozen Boundaries and Log Fronts

Speaker: 
Andrei Okounkov
Date: 
Mon, Oct 16, 2006
Location: 
University of British Columbia, Vancouver, Canada
Conference: 
PIMS 10th Anniversary Lectures
Abstract: 

In this talk, based on joint work with Richard Kenyon and Grisha Mikhalkin, Andrei Okounkov discusses a binary operation on plane curves which

  1. generalizes classical duality for plane curves and
  2. arises naturally in probabilistic context,

namely as a facet boundary in certain random surface models.

Class: 

On Long-Run Covariance Matrix Estimation with the Truncated Flat Kernel

Author: 
Shinichi Sakata
Date: 
Tue, Jun 3, 2008
Location: 
Simon Fraser University, Burnaby, Canada
Conference: 
PIMS Vancouver Econometrics Workshop
Abstract: 

Despite its large sample efficiency, the truncated flat (TF) kernel estimator of long-run covariance matrices is seldom used, because it lacks the guaranteed positive semidefiniteness and sometimes performs poorly in small samples, compared to other familiar kernel estimators. This paper proposes simple modifications to the TF estimator to enforce the positive definiteness without sacrificing the large sample efficiency and make the estimator more reliable in small samples through better utilization of the bias-variance tradeoff. We study the large sample properties of the modified TF estimators and verify their improved small-sample performances by Monte Carlo simulations.

Notes: 
Class: 

Modelling Aperiodic Solids: Concepts and Properties of Tilings and their Physical Interpretation

Author: 
Franz Gaehler
Date: 
Thu, Aug 1, 2002
Location: 
University of Victoria, Victoria, Canada
Conference: 
Aperiodic Order, Dynamical Systems, Operator Algebras and Topology
Abstract: 

Topics: Quasicrystals, Quasiperiodicity, Translation module, Repetitivity, Local Isomorphism, Mutual Local Derivability, Matching Rules, Covering Rules, Maximal Coverings

Class: 

Cohomology of Quasiperiodic Tilings

Author: 
Franz Gaehler
Date: 
Thu, Aug 1, 2002
Location: 
University of Victoria, Victoria, Canada
Conference: 
Aperiodic Order, Dynamical Systems, Operator Algebras and Topology
Abstract: 

Topics:

• Quasiperiodic tilings

• The hull of a tiling

• Approximation the hull by CW-spaces

• Application to canonical projection tilings

• Relation to matching rules

• Towards an interpretation

Class: 

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