## Past Events at the University of Calgary

### Past Events

- 26-Oct-07

Polytopes and arrangements: diameter and curvature

By analogy with the Hirsh conjecture, we conjecture that the order of the largest total curvature of the central path associated to a polytope is the number of inequalities defining the polytope. By analogy with a result of Dedieu, Malajovich and more››

Scientific Event

- 25-Oct-07

Klee-Minty cubes and the central path

We consider a family of LO problems over the n-dimensional Klee-Minty cube and show that the central path may visit all of its vertices in the same order as simplex methods do. This is achieved by carefully adding an exponential number of redundan more››

Scientific Event

- 24-Oct-07

Pivot v/s interior point methods: pros and cons

Linear Optimization (Programming) is probably the most successful and most intensively studied model in applied mathematics. First we give a survey of the governing algorithmic principles that lead to design Pivot and Interior Point Methods (IPMs) more››

Scientific Event

- 20-Oct-07
- 21-Oct-07

The 29th Annual Alberta Statisticians' Meeting

The 29th Annual Alberta Statisticians Meeting is sponsored by the Department of Mathematics and Statistics and the Faculty of Science at the University of Calgary, and also by PIMS. This meeting serves many purpose more››

Scientific Event

- 12-Oct-07

Unsolved for over twenty-five years, a surprisingly difficult conjecture stated that a non-crossing polygonal chain of fixed-length edges in the plane can be continuously opened without crossing. Gunter Rote, Erik Demaine and I proved this Carpent more››

Scientific Event

- 11-Oct-07

Why things don't fall down - Art, geometry and engineering

Why do some geometric shapes hold together, while others are floppy and fall down? An eggshell and a convex dome are rigid, while polygons, with four or more sides of fixed length in the plane, flex. The geometric principles for convex shapes go b more››

Scientific Event

- 10-Oct-07

The geometry of rigid and non-rigid structures

Convex triangulated surfaces in three-space are rigid by Cauchy's Theorem. But what about non-convex surfaces? Some interesting recent examples of classes of non-convex surfaces have some convex-like properties, and yet are still rigid. On the oth more››

Scientific Event

- 4-Oct-07

Total Positivity and its Applications

A matrix is called totally positive (resp. totally nonnegative)if all of its minors are positive (resp. nonnegative). This important class of matrices grew out of three separate applications: Vibrating systems, interpolation, and statistics. Since more››

Scientific Event

- 4-Oct-07

Scaling, universality and spatio-temporal clustering in seismicity and rock fracture phenomena

In this talk, Dr. Davidsen will give an overview of new methods from nonlinear sciences and complex network theory to characterize temporal and spatio-temporal clustering of point processes with a particular focus on their application to seismicity a more››

Industrial Event

- 3-Sep-07

The Intuitive Geometry Day in Calgary is a one-day meeting immediately following and extending the Intuitive Geometry Workhsop (August 31-September 2, 2007) held at the Banff International Research Station. The Intuitive Geometry Day is entir more››

Scientific Event

- 23-Jul-07
- 28-Jul-07

http://nanotech.ucalgary.ca/dsfd2007/ more››

Scientific Event

- 4-May-07
- 6-May-07

Western Canadian Conference for Young Researchers in Mathematics

Dear Graduate Students, Welcome to our conference website! This conference provides graduate students with a forum to discuss their research. With funds from PIMS and the University of Calgary, we can provide you with accommodat more››

Scientific Event

- 19-Apr-07

Gauss Sums: Finding the Root of Unity

A Gauss sum over a finite field GF(q) is a sum of q algebraic numbers. It is often useful to evaluate Gauss sums explicitly, for instance, in coding theoretic or cryptographic applications. For small q, the evaluation of Gauss sums can be done nai more››

Scientific Event

- 18-Apr-07

Values and Ideals in Combinatorial Problems

The absolute value of complex numbers is surprisingly useful in the investigation of certain combinatorial problems. The connection often arises from imbedding finite cyclic groups into the complex numbers by sending the group elements to roots of more››

Scientific Event

- 9-Mar-07

Amoebas, Coamoebas, and Tropical Geometry

Given a triangle with side lengths 1, log x, log y and opposite interior angles π-u-v, u, v, the functional determinant ∂(x,y)/∂(u,v) is identically equal to 1. This amusing fact is a special ins more››

Scientific Event

- 7-Dec-06

Time-Frequency Analysis: From Wireless Communications to Abstract Harmonic Analysis

In the talk I will discuss the relation between problems in wireless communications and time-frequency analysis. I will explain the basic principle of OFDM (orthogonal frequency division multiplexing) and its formulation in time-frequency analysis more››

Scientific Event

- 1-Dec-06

Energy minimization can be thought of as a broad generalization of sphere packing. Yudin discovered that harmonic analysis can be applied to prove lower bounds for potential energy. This talk will explain these bounds and show how to use them to p more››

Scientific Event

- 30-Nov-06

Optimality of the Leech lattice

This talk will outline the proof that the Leech lattice is the unique densest lattice in R24. The proof combines linear programming bounds with special algebraic and geometric arguments. This is joint work with Abhinav Kumar. more››

Scientific Event

- 29-Nov-06

Sphere packing and harmonic analysis

Harmonic analysis is one of the fundamental tools in sphere packing, in the form of "linear programming bounds". This talk will give a survey of linear programming bounds and their applications, as well as a brief introduction to semidef more››

Scientific Event

- 17-Nov-06

Scientific Event