A measure of connectivity using the ratio of the number of circuits in a network to the maximum possible in that network. The higher the alpha index, the more a network is connected. A value of 1 indicates a completely connected network, but ‘it is very rare that a network will have an alpha value of 1, because this would imply very serious redundancies’ (J.-P. Rodrigue2006). The alpha index is given as:α=u2v-5where u is the maximum number of independent cycles in a graph, estimated through the number of nodes (v), links (e), and of sub-graphs (p); u = e − v + p.
Subjects: Earth Sciences and Geography.