Events by date

David Chodounsky, Institute of Mathematics of the Czech Academy of Sciences

"Countable chromatic number of definable graphs via games"

We define games which characterize countable coloring numbers of analytic graphs on Polish spaces. These games can provide simple verification of the countable chromatic number of certain graphs. (Eg. the rational distance graph on the Euclidean plane.) Joint work with Jindrich Zapletal.

MC 5403

Francisco Villacis, Department of Pure Mathematics, University of Waterloo

"An Introduction to GIT Quotients"

Ada Chan, York University

"Complex Hadamard matrices and association schemes, Part 1"

Complex Hadamard matrices and spin models are special cases of type-II matrices. In the 1980s, Vaughan Jones used spin models to construct link invariants and representations of braid groups. The term type II was coined after the second Reidemeister move of link diagrams. In 1990s, Jaeger and Nomura discovered the surprising connection of spin models and association schemes.

Rahim Moosa, Department of Pure Mathematics, University of Waterloo

"Restricted Zilber Trichotomy"

We will be reading Ben Castle’s paper.

MC 4060