Online Minimization of Polarization and Disagreement via Low-Rank Matrix Bandits

Fuente: arXiv
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Autori principali: Cinus, Federico, Kuroki, Yuko, Miyauchi, Atsushi, Bonchi, Francesco
Natura: Preprint
Pubblicazione: 2025
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author Cinus, Federico
Kuroki, Yuko
Miyauchi, Atsushi
Bonchi, Francesco
author_facet Cinus, Federico
Kuroki, Yuko
Miyauchi, Atsushi
Bonchi, Francesco
contents We study the problem of minimizing polarization and disagreement in the Friedkin-Johnsen opinion dynamics model under incomplete information. Unlike prior work that assumes a static setting with full knowledge of agents' innate opinions, we address the more realistic online setting where innate opinions are unknown and must be learned through sequential observations. This novel setting, which naturally mirrors periodic interventions on social media platforms, is formulated as a regret minimization problem, establishing a key connection between algorithmic interventions on social media platforms and the theory of multi-armed bandits. In our formulation, a learner observes only a scalar feedback of the overall polarization and disagreement after an intervention. For this novel bandit problem, we propose a two-stage algorithm based on low-rank matrix bandits. The algorithm first performs subspace estimation to identify an underlying low-dimensional structure, and then employs a linear bandit algorithm within the compact dimensional representation derived from the estimated subspace. We show that our algorithm achieves the cumulative regret of $\widetilde{\mathcal{O}}\big(\max(\tfrac{1}κ,\sqrt{|V|})\sqrt{|V|T}\big)$ over time horizon $T$, where $V$ is the set of agents and $κ$ is a parameter dependent on the diversity of interventions. Empirical results validate that our algorithm significantly outperforms a linear bandit baseline in terms of both cumulative regret and running time.
format Preprint
id arxiv_https___arxiv_org_abs_2510_00803
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Online Minimization of Polarization and Disagreement via Low-Rank Matrix Bandits
Cinus, Federico
Kuroki, Yuko
Miyauchi, Atsushi
Bonchi, Francesco
Machine Learning
Social and Information Networks
We study the problem of minimizing polarization and disagreement in the Friedkin-Johnsen opinion dynamics model under incomplete information. Unlike prior work that assumes a static setting with full knowledge of agents' innate opinions, we address the more realistic online setting where innate opinions are unknown and must be learned through sequential observations. This novel setting, which naturally mirrors periodic interventions on social media platforms, is formulated as a regret minimization problem, establishing a key connection between algorithmic interventions on social media platforms and the theory of multi-armed bandits. In our formulation, a learner observes only a scalar feedback of the overall polarization and disagreement after an intervention. For this novel bandit problem, we propose a two-stage algorithm based on low-rank matrix bandits. The algorithm first performs subspace estimation to identify an underlying low-dimensional structure, and then employs a linear bandit algorithm within the compact dimensional representation derived from the estimated subspace. We show that our algorithm achieves the cumulative regret of $\widetilde{\mathcal{O}}\big(\max(\tfrac{1}κ,\sqrt{|V|})\sqrt{|V|T}\big)$ over time horizon $T$, where $V$ is the set of agents and $κ$ is a parameter dependent on the diversity of interventions. Empirical results validate that our algorithm significantly outperforms a linear bandit baseline in terms of both cumulative regret and running time.
title Online Minimization of Polarization and Disagreement via Low-Rank Matrix Bandits
topic Machine Learning
Social and Information Networks
url https://arxiv.org/abs/2510.00803