Title: A deterministic (1/2 + epsilon)-approximation for submodular maximizztion over a matroidSpeaker: Ben Moore Affiliation: University of Waterloo Room: MC 5417
In 1978, it was shown that a natural greedy algorithm gives a 1/2 approximation to submodular maximization subject to a matroid constraint.
Title: The combinatorics of parametric Feynman integralsSpeaker: Marcel Golz Affiliation: University of Waterloo Room: MC 5501
Feynman integrals are used in perturbative quantum field theory to compute the probabilities of processes involving elementary particles. They can be represented as Feynman graphs and exhibit a rich combinatorial structure. The parametric representation of Feynman integrals is particularly suitable to be studied from a combinatorial perspective since it contains well known objects like the Kirchhoff polynomial.