@article {2011,
	title = {Computing global structural balance in large-scale signed social networks.},
	journal = {Proceedings of the National Academy of Sciences of the United States of America. Volume 108, Issue 52, 27 December 2011, Pages 20953-20958},
	number = {PMID:22167802;},
	year = {2011},
	note = {Free fulltext article in Pubmed Central},
	publisher = {National Academy of Sciences},
	abstract = {Structural balance theory affirms that signed social networks (i.e., graphs whose signed edges represent friendly/hostile interactions among individuals) tend to be organized so as to avoid conflictual situations, corresponding to cycles of negative parity. Using an algorithm for ground-state calculation in large-scale Ising spin glasses, in this paper we compute the global level of balance of very large online social networks and verify that currently available networks are indeed extremely balanced. This property is explainable in terms of the high degree of skewness of the sign distributions on the nodes of the graph. In particular, individuals linked by a large majority of negative edges create mostly \\\"apparent disorder,\\\" rather than true \\\"frustration.\\\"},
	keywords = {Combinatorial optimization},
	doi = {10.1073/pnas.1109521108},
	url = {http://hdl.handle.net/1963/6426},
	author = {Giuseppe Facchetti and Giovanni Iacono and Claudio Altafini}
}
