Date: Friday, January 29, 2016
Location: BBB (Room TBA) (10:00 AM to 11:00 AM)
Title: Using Expander Graphs to Find Vertex Connectivity
Abstract: The (vertex) connectivity ? of a graph is the smallest number of vertices whose deletion separates the graph or makes it trivial. We present the fastest known algorithm for finding ?. For a digraph with n vertices, m edges and connectivity ? the time bound is O((n + min{?^5/2, ?n^3/4})m). This improves the previous best bound of O((n + min{?^3, ?n})m). For an undirected graph both of these bounds hold with m replaced by ?n. Expander graphs are useful for solving the following subproblem that arises in connectivity computation: A known set R of vertices contains two large but unknown subsets that are separated by some unknown set S of ? vertices; we must find two vertices of R that are separated by S.
This work is by Harold N Gabow (2006).
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Speaker: ShangEn Huang
Institution: UM
Event Organizer: schoeneb
