Fast and Compact Webgraph Representations

Abstract

Compressed graph representations, in particular for Web graphs, have become an attractive research topic because of their applications in the manipulation of huge graphs in main memory. This seminar deal with two grammar-based compression mechanisms that used to compress the web graph. I focus on Re-Pair and on Ziv-Lempel compression, which, although cannot reach the best compression ratios of WebGraph, achievemuch faster navigation of the graph when both are tuned to use the same space. Moreover,the technique adapts well to run on secondary memory and in distributed scenarios. As a byprod- uct, we introduce an approximate Re-Pair version that works efficiently with severely limited main memory.