Reference Work Entry

Encyclopedia of Complexity and Systems Science

pp 5692-5702

Motifs in Graphs

  • Sergi ValverdeAffiliated withComplex Systems Lab, Parc de Recerca Biomedica de Barcelona
  • , Ricard V. SoléAffiliated withSanta Fe Institute

Definition of the Subject

Several nested levels of organization can be defined for any complex system, being many of such levels describable in terms of some type of networkpattern. In this context, complex networks both in nature and technology have been shown to display overabundance of some characteristic, small subgraphs(so called motifs) which appear to be characteristic of the class of network considered. These tiny modules offer a powerful way of classifyingnetworks and are the fingerprints of the rules generating network complexity.


Complex systemscan be described, on a first approximation by means of a network [1,3,5,19]. In such a network, the typical components of the system (atoms, proteins, species, computers, humans or neurons)are simply nodes with no further structure. They are linked to others by means of an edge. The presence of such a link implies that there is some type ofcausal relation. Such relation can b ...

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