Harmonic Centrality

The denormalized reciprocal of the harmonic mean of all distances (even ∞).
Another extension to networks with disconnected components has been proposed by Opsahl (2010) and later studied by Boldi and Vigna (2014) in general directed graphs: The formula above, with the convention, defines harmonic centrality. It is a natural modification of Bavelas's definition of closeness following the general principle proposed by Marchiori and Latora (2000) that in networks with infinite distances the harmonic mean behaves better than the arithmetic mean. Indeed, Bavelas's closeness can be described as the denormalized reciprocal of the arithmetic mean of distances, whereas harmonic centrality is the denormalized reciprocal of the harmonic mean of distances.

The harmonic mean H of the positive real numbers x1, x2, ..., xn > 0 is defined to be:

See Information Centrality

• WebGraph
  http://webgraph.di.unimi.it/

• BOLDI, P. & VIGNA, S. 2014. Axioms for centrality. Internet Mathematics, 00-00.
• MARCHIORI, M. & LATORA, V. 2000. Harmony in the small-world. Physica A: Statistical Mechanics and its Applications, 285, 539-546.
• OPSAHL, T., AGNEESSENS, F. & SKVORETZ, J. 2010. Node centrality in weighted networks: Generalizing degree and shortest paths. Social Networks, 32, 245-251.
• OPSAHL, T. 2010. Closeness centrality in networks with disconnected components (http://toreopsahl.com/2010/03/20/closeness-centrality-in-networks-with-disconnected-components/)