ARC Colloquium: David Karger (MIT)

Video of this talk is available at:

Full collection of talk videos are available at:

Algorithms & Randomness Center (ARC)

David Karger - MIT

Monday, September 26, 2016
Klaus 1116 East - 11:00 am

A Fast and Simple Unbiased Estimator for Network (Un)reliability

The following procedure yields an unbiased estimator for the disconnection probability of an n-vertex graph with minimum cut c if every edge fails independently with probability p: (i) contract every edge independently with probability 1-n^{-2/c}, then (ii) recursively compute the disconnection probability of the resulting tiny graph if each edge fails with probability n^{2/c}p.  We give a short, simple, self-contained proof that this estimator can be computed in linear time and has relative variance O(n^2).  Combining these two facts with a relatively standard sparsification argument yields an O(n^3\log n)-time algorithm for estimating the (un)reliability of a network.  We also show how the technique can be used to create unbiased samples of disconnected networks.

Speaker's webpage:
Fall 2016 ARC Seminar Schedule:


Event Details


  • Monday, September 26, 2016
    11:00 am - 12:00 pm
Location: Klaus 1116 East

For More Information Contact

Dani Denton

denton at cc dot gatech dot edu