Random k-out subgraphs

Or Zamir, Princeton University and IAS
Fine Hall 224

In-Person Talk 

Each vertex of an arbitrary simple graph on n vertices chooses k random incident edges. What is the expected number of edges in the original graph that connect different connected components of the sampled subgraph? We prove that the answer is O(n/k), when k ≥ c log n, for some large enough c. We conjecture that the same holds for smaller values of k, possibly for any k ≥ 2. Such a result is best possible for any k ≥ 2. We give applications of this sampling lemma for models of distributed algorithms.

Based on joint work with Jacob Holm, Valeria King, Mikkel Thorup and Uri Zwick.