Beyond Monotonicity: Revisiting Factorization Principles in Multi-Agent Q-Learning

Fuente: arXiv
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Autori principali: Hu, Tianmeng, Cui, Yongzheng, Tang, Rui, Luo, Biao, Li, Ke
Natura: Preprint
Pubblicazione: 2025
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author Hu, Tianmeng
Cui, Yongzheng
Tang, Rui
Luo, Biao
Li, Ke
author_facet Hu, Tianmeng
Cui, Yongzheng
Tang, Rui
Luo, Biao
Li, Ke
contents Value decomposition is a central approach in multi-agent reinforcement learning (MARL), enabling centralized training with decentralized execution by factorizing the global value function into local values. To ensure individual-global-max (IGM) consistency, existing methods either enforce monotonicity constraints, which limit expressive power, or adopt softer surrogates at the cost of algorithmic complexity. In this work, we present a dynamical systems analysis of non-monotonic value decomposition, modeling learning dynamics as continuous-time gradient flow. We prove that, under approximately greedy exploration, all zero-loss equilibria violating IGM consistency are unstable saddle points, while only IGM-consistent solutions are stable attractors of the learning dynamics. Extensive experiments on both synthetic matrix games and challenging MARL benchmarks demonstrate that unconstrained, non-monotonic factorization reliably recovers IGM-optimal solutions and consistently outperforms monotonic baselines. Additionally, we investigate the influence of temporal-difference targets and exploration strategies, providing actionable insights for the design of future value-based MARL algorithms.
format Preprint
id arxiv_https___arxiv_org_abs_2511_09792
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Beyond Monotonicity: Revisiting Factorization Principles in Multi-Agent Q-Learning
Hu, Tianmeng
Cui, Yongzheng
Tang, Rui
Luo, Biao
Li, Ke
Machine Learning
Multiagent Systems
I.2.6
Value decomposition is a central approach in multi-agent reinforcement learning (MARL), enabling centralized training with decentralized execution by factorizing the global value function into local values. To ensure individual-global-max (IGM) consistency, existing methods either enforce monotonicity constraints, which limit expressive power, or adopt softer surrogates at the cost of algorithmic complexity. In this work, we present a dynamical systems analysis of non-monotonic value decomposition, modeling learning dynamics as continuous-time gradient flow. We prove that, under approximately greedy exploration, all zero-loss equilibria violating IGM consistency are unstable saddle points, while only IGM-consistent solutions are stable attractors of the learning dynamics. Extensive experiments on both synthetic matrix games and challenging MARL benchmarks demonstrate that unconstrained, non-monotonic factorization reliably recovers IGM-optimal solutions and consistently outperforms monotonic baselines. Additionally, we investigate the influence of temporal-difference targets and exploration strategies, providing actionable insights for the design of future value-based MARL algorithms.
title Beyond Monotonicity: Revisiting Factorization Principles in Multi-Agent Q-Learning
topic Machine Learning
Multiagent Systems
I.2.6
url https://arxiv.org/abs/2511.09792