CS Colloquium

Speaker: Sasha Alexander Sherstov, Microsoft Research

Talk Title: Limits of Communication

Abstract: Consider a function f whose arguments are distributed among several parties, making it impossible for any one party to compute f in isolation. Initiated in 1979, communication complexity theory studies how many bits of communication are needed to evaluate f. I will prove that:

1. some natural and practical problems require high communication to achieve any advantage at all over random guessing;
2. solving n instances of any known communication problem on a quantum computer incurs Omega(n) times the cost of a single instance, even to achieve exponentially small correctness probability.

The proofs work by recasting the communication problem geometrically and looking at the dual problem in a novel way. Our results resolve open problems dating back to 1986.



Biography: Alexander Sherstov earned his Ph.D. in computer science in August 2009 at the University of Texas at Austin, under the direction of Prof. Adam Klivans, and is currently a postdoctoral researcher at Microsoft Research. He has broad research interests in theoretical computer science, including complexity theory, computational learning theory, and quantum computing.

Host: Prof. Ming-Deh Huang

Location: SAL 101

Audiences: Everyone Is Invited

Contact: Kanak Agrawal