Chapter 8. Analyze and Understand Networks Using R

Network analysis is the study of graphs. Graphs are defined by a set of nodes or vertices connected by edges. Both the nodes and vertices can have attributes describing them. Most importantly, the edges can carry weight, indicating the importance of the connection. When the directions of the edges are preserved, the graph is called a directed graph; when not preserved, it's called an undirected graph. Network analysis, or network theory, or graph theory provides a rich set of algorithms to analyze and understand graphs. The famous Koenigsberg problem (http://mathworld.wolfram.com/KoenigsbergBridgeProblem.html) introduced by Euler is one of the first graph theory problems to be studied. Koenigsberg is an old city in Prussia (modern day Russia). The river Pregal separates the city. There are two other islands. There are seven bridges connecting the islands and the cities. The Koenigsberg problem was to devise a walk through the city that would...