2006-2007 seminars

Dec
13
2006

Computer Science/Discrete Mathematics Seminar III

Permanents, Determinants and Non-Commutativity
Alistair Sinclair
11:15am|West Building Lecture Theatre

All known efficient algorithms for computing the determinant of a matrix rely on commutativity of the matrix entries. How important is this property, and could we make use of an algorithm that computes determinants without assuming commutativity? In...

Dec
12
2006

Computer Science/Discrete Mathematics Seminar II

Cycles and Cliques Minors in Expanders
Benny Sudakov
10:30am|S-101

Let $G$ be a graph which contains no subgraphs isomorphic to fixed bipartite graph $H$. Using well known results from Extremal Graph theory, one can show that such $G$ has certain expansion properties, i.e., all small subsets of $G$ have large...

Dec
11
2006

Computer Science/Discrete Mathematics Seminar I

Approximation Algorithms for Combinatorial Allocation Problems
11:15am|S-101

In combinatorial allocation, m items are to be assigned to n players so that their total utility is maximized. This problem has many variants depending on the utility functions involved and possible additional constraints. We consider two variants...

Dec
05
2006

Computer Science/Discrete Mathematics Seminar II

On the Correlation Between Parity and Modular Polynomials
10:30am|S-101

We consider the problem of bounding the absolute value of the correlation between parity and low-degree polynomials modulo q, for odd q >= 3. The boolean function corresponding to the polynomial is 0 on an input iff the polynomial evaluates to 0...

Dec
04
2006

Computer Science/Discrete Mathematics Seminar I

Transparent Achievement of Correlated Equilibrium
Silvio Micali
11:15am|S-101

Achieving correlated equilibrium is a problem at the intersection of game theory, cryptography and efficient algorithms. Thus far, however, perfectly rational solutions have been lacking, and the problem has been formulated with somewhat limited...

Nov
28
2006

Computer Science/Discrete Mathematics Seminar II

New Correlation Bounds for GF(2) Polynomials Using the Gowers Norm
10:30am|S-101

In this work we study the correlation between low-degree GF(2) polynomials and explicit functions, where the correlation between two functions f,p : {0,1}^n -> {+1,-1} is defined as Correlation(p,f) := | E_x [f(x) p(x)] | = | P_x[f(x) = p(x)] - P_x...

Nov
27
2006

Computer Science/Discrete Mathematics Seminar I

New Locally Decodable Codes and Private Information Retrieval Schemes
11:15am|S-101

A q-query Locally Decodable Code (LDC) encodes an n-bit message x as an N-bit codeword C(x), such that one can probabilistically recover any bit x_i of the message by querying only q bits of the codeword C(x), even after some constant fraction of...

Nov
14
2006

Computer Science/Discrete Mathematics Seminar II

Cut Problems in Graphs: Algorithms and Complexity
10:30am|S-101

Cut problems are fundamental to combinatorial optimization, and they naturally arise as intermediate problems in algorithm design. The study of cut problems is inherently connected to the dual notion of flows. In particular, starting with the...