Discovering polarized communities in signed networks

Francesco Bonchi, Aristides Gionis, Bruno Ordozgoiti, Edoardo Galimberti, Giancarlo Ruffo

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

7 Citations (Scopus)


Signed networks contain edge annotations to indicate whether each interaction is friendly (positive edge) or antagonistic (negative edge). The model is simple but powerful and it can capture novel and interesting structural properties of real-world phenomena. The analysis of signed networks has many applications from modeling discussions in social media, to mining user reviews, and to recommending products in e-commerce sites. In this paper we consider the problem of discovering polarized communities in signed networks. In particular, we search for two communities (subsets of the network vertices) where within communities there are mostly positive edges while across communities there are mostly negative edges. We formulate this novel problem as a “discrete eigenvector” problem, which we show to be NP-hard. We then develop two intuitive spectral algorithms: one deterministic, and one randomized with quality guarantee √n (where n is the number of vertices in the graph), tight up to constant factors. We validate our algorithms against non-trivial baselines on real-world signed networks. Our experiments confirm that our algorithms produce higher quality solutions, are much faster and can scale to much larger networks than the baselines, and are able to detect ground-truth polarized communities.

Original languageEnglish
Title of host publicationCIKM 2019 - Proceedings of the 28th ACM International Conference on Information and Knowledge Management
Number of pages10
ISBN (Electronic)9781450369763
Publication statusPublished - 3 Nov 2019
MoE publication typeA4 Article in a conference publication
EventACM International Conference on Information and Knowledge Management - Beijing, China
Duration: 3 Nov 20197 Nov 2019
Conference number: 28

Publication series

NameInternational Conference on Information and Knowledge Management, Proceedings


ConferenceACM International Conference on Information and Knowledge Management
Abbreviated titleCIKM

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