Seminars

Oct
14
2014

Computer Science/Discrete Mathematics Seminar II

Sampling-based proof of the quasipolynomial Bogolyubov-Ruzsa theorem and algorithmic applications
10:30am|West Bldg. Lect. Hall

The polynomial Bogolyubov-Ruzsa conjecture which aims to quantify the amount of additive structure in dense subsets of abelian groups is one of the central conjectures in additive combinatorics which has recently been shown to have various...

Oct
13
2014

Computer Science/Discrete Mathematics Seminar I

Cool with a Gaussian: an \(O^*(n^3)\) volume algorithm
Santosh Vempala
11:15am|West Bldg. Lect. Hall

Computing the volume of a convex body in n-dimensional space is an ancient, basic and difficult problem (#P-hard for explicit polytopes and exponential lower bounds for deterministic algorithms in the oracle model). We present a new algorithm, whose...

Oct
07
2014

Computer Science/Discrete Mathematics Seminar II

Monotone submodular maximization over a matroid
10:30am|S-101

Monotone submodular maximization over a matroid (MSMM) is a fundamental optimization problem generalizing Maximum Coverage and MAX-SAT. Maximum Coverage is NP-hard to approximate better than \(1-1/e\), an approximation ratio obtained by the greedy...

Oct
06
2014

Computer Science/Discrete Mathematics Seminar I

The communication complexity of distributed subgraph detection
Rotem Oshman
11:15am|S-101

In distributed systems, communication between the participants in the computation is usually the most expensive part of the computation. Theoretical models of distributed systems usually reflect this by neglecting the cost of local computation, and...

Sep
30
2014

Computer Science/Discrete Mathematics Seminar II

Uniform words are primitive (cont'd)
10:30am|S-101

Let \(G\) be a finite group, and let \(a\), \(b\), \(c\),... be independent random elements of \(G\), chosen at uniform distribution. What is the distribution of the element obtained by a fixed word in the letters \(a\), \(b\), \(c\),..., such as \...

Sep
29
2014

Computer Science/Discrete Mathematics Seminar I

Breaking \(e^n\) barrier for deterministic poly-time approximation of the permanent and settling Friedland's conjecture on the Monomer-Dimer Entropy
11:15am|S-101

Two important breakthroughs on the permanent had been accomplished in 1998: A. Schrijver proved Schrijver-Valiant Conjecture on the minimal exponential growth of the number of perfect matchings in k-regular bipartite graphs with multiple edges; N...

Sep
23
2014

Computer Science/Discrete Mathematics Seminar II

Uniform words are primitive
10:30am|S-101

Let \(G\) be a finite group, and let \(a\), \(b\), \(c\),... be independent random elements of \(G\), chosen at uniform distribution. What is the distribution of the element obtained by a fixed word in the letters \(a\), \(b\), \(c\),..., such as \...

Sep
22
2014

Computer Science/Discrete Mathematics Seminar I

Colouring graphs with no odd holes
Paul Seymour
11:15am|S-101

The chromatic number \(k(G)\) of a graph \(G\) is always at least the size of its largest clique (denoted by \(w(G)\)), and there are graphs with \(w(G)=2\) and \(k(G)\) arbitrarily large. On the other hand, the perfect graph theorem asserts that if...