Simon Fraser University

Abstract A frequent problem in forecasting fog or icy roads in a numerical weather prediction system is attributed to the misinterpretation of the boundary layer structure in the assimilation procedure. Case studies showed that much of the...

Abstract: Santos' recent construction of a counterexample to the Hirsch conjecture highlights a particular 5-dimensional ``prismatoid'' polytope.We use the Euler characteristicto prove that there is no analogous 4-dimensional prismatoid. This is...

Petr Škoda Abstract:We study the obstructions (minor-minimal forbidden graphs) for orientable surfaces that have a 2-vertex cut. The building blocks of the obstructions are described. As a consequence, the complete list of 68 obstructions for the...

Abstract: The graph isomorphism (GI) problem asks if two given graphs are isomorphic or not. That is, it asks there exists a one-to-one mapping between two given graphs. The GI problem is quite basic, but it's time complexity isa long standing open...

Abstract: Garg Vazarani and Yannakakis showed that the integrality gap for (the natural LP relaxation of) maximum disjoint paths (MEDP) in planar graphs is $\\Omega(\\sqrt{n})$. Noting that their gap example (a grid minor) all but disappears if edge...

Abstract: An \\emph{intertwine} of two graphs $G$ and $H$ is a graph that has both $G$ and $H$ as a minor and is minor-minimal with this property. In 1979, Lov\\'{a}sz and Unger conjectured that for any two graphs $G$ and $H$, there are only a finite...

Abstract: The body-centered cubic (BCC) lattice is the optimal three-dimensional sampling lattice. Its optimality stems from the fact that its dual, the face-centered cubic (FCC) lattice, achieves the highest sphere-packing efficiency. In order to...

The goal of this event is to link our research programs and students and provide a jumping off point for future collaboration.

David Blackwell preferred to write short, direct papers dissectingproblems cleanly and showing the rest of us why things have to be theway they are. I plan to talk about David's life, describe a few of thethings he is famous for (Markov Chains...