Let's go back to the graph we started analyzing in the first section. The following diagram shows a comparison of several of the centrality algorithms we studied in this chapter:
If degree centrality can't differentiate between four nodes that all have three connections (nodes 3, 5, 6, and 9), PageRank is able to make some nodes stand out from the crowd by giving more importance to nodes 3 and 6. Closeness and betweenness both clearly identify node 5 as the most critical: if this node disappears, the paths within the graph will be completely changed or even impossible, as we discussed in the first section of this chapter.
Centrality algorithms have many types of applications. In the next section, we will review some of them, starting from the fraud detection use case.
