Events - 2018

Title: Aggregation-based cutting-planes for packing and covering integer programs

Abstract:

We study the strength of Chvatal-Gomory (CG) cuts and more generally aggregation cuts for packing and covering integer programs (IPs).

Title: Flag algebras and subgraph density problems

Abstract: Flag algebras are a tool introduced by Razborov in 2007 that has since been successfully used to approach or solve many problems in asymptotic extremal combinatorics.

The "blood, sweat, tears, toil and triumphs" of commercializing technology

Title: The upper density of monochromatic infinite paths

Abstract: Given a complete graph $K_n$, whose edges are coloured in red and blue, what is the longest monochromatic path one can find?

Title: Solving DNN Relaxations of the Quadratic Assignment Problem with ADMM and Facial Reduction

Abstract:

The quadratic assignment problem, QAP, has many important applications ranging from the planning of building locations of a university, to the positioning of modules on a computer chip (VLSI design), to the design of keyboards.

Title:  A Short Proof of the Containers Theorem for Hypergraphs

Abstract:  A modern trend in extremal combinatorics is extending classical results from the dense setting (e.g. Szemerédi's theorem)

Title: Approximation Algorithms for Distributionally Robust Stochastic Optimization

Abstract:

Two-stage stochastic optimization is a widely-used framework for modeling uncertainty, where we have a probability distribution over possible realizations of the data, called scenarios, and decisions are taken in two stages: we make first-stage decisions knowing only the underlying distribution and before a scenario is realized, and may take additional second-stage recourse actions after a scenario is realized.

Title:  2-universality of random graphs.

Abstract: For a family of graphs F, a graph G is F-universal if G contains every graph in F as a (not necessarily induced) subgraph.

Title: Razborov's flag algebras: Ten years on

Abstract:

Many of the classical results in extremal combinatorics were obtained by ingenious application of elementary techniques, such as induction and Cauchy-Schwarz inequality.

Title: Vertex Minors

Abstract:

I will give an introduction to vertex-minors of graphs. At first sight vertex minors are a bit peculiar but they are closely related to graph minors and possibly even easier to work with.

Title: Some problems on the size Ramsey numbers

Abstract: For given simple graphs $G_1$ and $G_2$, the size Ramsey number $\hat{R}(G_1,G_2)$ is the smallest positive integer $m$,