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Updated: Feb 15, 2026

Analyzing the Size, Shape, and Directionality of Networks of Coupled Astrocytes
Published on: October 4, 2018
Resolution of ranking hierarchies in directed networks
Elisa Letizia1, Paolo Barucca2,3, Fabrizio Lillo4
1Scuola Normale Superiore, Piazza dei Cavalieri 7, Pisa, 56126, Italy.
Abstract:
Identifying hierarchies and rankings of nodes in directed graphs is fundamental in many applications such as social network analysis, biology, economics, and finance. A recently proposed method identifies the hierarchy by finding the ordered partition of nodes which minimises a score function, termed agony. This function penalises the links violating the hierarchy in a way depending on the strength of the violation. To investigate the resolution of ranking hierarchies we introduce an ensemble of random graphs, the Ranked Stochastic Block Model. We find that agony may fail to identify hierarchies when the structure is not strong enough and the size of the classes is small with respect to the whole network. We analytically characterise the resolution threshold and we show that an iterated version of agony can partly overcome this resolution limit.
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