The '''Girvan-Newman algorithm''' is one of the methods used to detect communities in complex systems.<ref name=newman>Girvan M. and Newman M. E. J., Proc. Natl. Acad. Sci. USA '''99''', 7821-7826 (2002)</ref> The notion of a "community structure" is differentrelated thanto that of clustering. The latter refers to the "small-world" property of a certain group of nodes within a network, wherethough theit [[averageisn't path length]] <math>\ell</math> amongquite the nodes is relatively smallsame. A community instead,consists isof a subset of nodes within which the node-node connections are dense, and the edges amongto nodes in other communities are less dense.<ref name=newman/> A simplified version of a network containing communities in it is shown in Fig. 1. An There are numerous alternative method for the detection ofdetecting communities withinin networks. istheThese include [[Hierarchical Clustering | hierarchical clustering]], partitioning graphs to maximize quality functions such as [[modularity]], k-clique percolation, etc.
