2008-2009 Seminars

Oct
14
2008

Computer Science/Discrete Mathematics Seminar II

Lower Bounds for Circuits with MOD_m Gates
10:30am|S-101

A celebrated theorem of Razborov/Smolensky says that constant depth circuits comprising AND/OR/MOD_{p^k} gates of unbounded fan-in, require exponential size to compute the MAJORITY function if p is a fixed prime and k is a fixed integer. Extending...

Oct
13
2008

Computer Science/Discrete Mathematics Seminar I

Average Case to Worst Case Reductions for Polynomials
11:15am|S-101

We study the model of approximation and calculation of constant degree multivariate polynomials over finite fields. We prove that if a constant degree polynomial can be approximated by a function of a constant number of lower degree polynomials, it...

Oct
07
2008

Computer Science/Discrete Mathematics Seminar II

Lower Bounds for Circuits with MOD_m Gates
10:30am|S-101

A celebrated theorem of Razborov/Smolensky says that constant depth circuits comprising AND/OR/MOD_{p^k} gates of unbounded fan-in, require exponential size to compute the MAJORITY function if p is a fixed prime and k is a fixed integer. Extending...

Oct
06
2008

Members’ Seminar

Color Coding, Balanced Hashing and Approximate Counting
2:00pm|S-101

Color Coding is an algorithmic technique for deciding efficiently if a given input graph contains a path of a given length (or another small subgraph of a certain type). It illustrates well the phenomenon that probabilistic reasoning can be helpful...

Oct
06
2008

Computer Science/Discrete Mathematics Seminar I

List-Decoding Reed-Muller Codes Over Small Fields
11:15am|S-101

We present the first local list-decoding algorithm for the r-th order Reed-Muller code RM(r,m) over F_2 for r>1 . Given an oracle for a received word R: F_2^m to F_2 , our randomized local list-decoding algorithm produces a list containing all...

Sep
30
2008

Computer Science/Discrete Mathematics Seminar II

A Survey of Time Lower Bounds by Algorithmic Arguments
10:30am|S-101

One natural strategy for proving a time lower bound for a problem is proof-by-contradiction: assume that there is a great algorithm for the problem, and apply this algorithm as a subroutine to solve other problems until the algorithms get so great...

Sep
29
2008

Computer Science/Discrete Mathematics Seminar I

Composition of Rational Functions
Michael Zieve
11:15am|S-101

I will discuss this problem: given rational functions f and g over a field K , determine whether there are nonconstant rational functions u and v over K such that u(f(x)) = v(g(x)) . An equivalent problem is to compute the intersection of two fields...

Sep
23
2008

Computer Science/Discrete Mathematics Seminar II

Multilinear Computation
10:30am|S-101

Nisan and Wigderson defined the model of multilinear circuits as a natural model for computing multilinear polynomials (such as matrix product and the Permanent). We will go over several results regarding such circuits -- a few structural results...

Sep
16
2008

Computer Science/Discrete Mathematics Seminar II

Multilinear Computation
10:30am|S-101

Nisan and Wigderson defined the model of multilinear circuits as a natural model for computing multilinear polynomials (such as matrix product and the Permanent). We will go over several results regarding such circuits -- a few structural results...