arXiv AI

On Symmetry for Characterizing Agent Heterogeneity in Multi-Agent Systems

arXiv Machine Learning
Jun 8

High entropy leads to symmetry-equivariant policies in Dec-POMDPs

arXiv:2511. 22581v5 Announce Type: replace Abstract: We prove that in any Dec-POMDP, sufficiently high entropy regularization ensures that the policy gradient flow with tabular softmax parametrization always converges, for any initialization, to the same joint policy, and that this joint policy is equivariant w.

By Johannes Forkel, Constantin Ruhdorfer, Michael Beukman, Andreas Bulling, Jakob Foerster
arXiv AI
Sep 24

Evolutionary Stability Does Not Guarantee Learning Accessibility: A Multi-Agent Reinforcement Learning Perspective on Cooperation Emergence

The paper investigates whether evolutionary stability guarantees that learning agents can achieve cooperative outcomes in a multi‑agent setting. Using a three‑agent governance game, the authors compare the evolutionary basin of attraction with learning basins derived from independent Q‑learning, scaled Boltzmann exploration, and SA–EA BQL. They find that while the evolutionary basin covers the entire sampled grid, only ε‑greedy Q‑learning attains a substantial learning basin, whereas the other methods fail to sustain cooperation, highlighting a disconnect between population‑level stability and finite‑sample learning accessibility.

By Yijie Wang
arXiv AI
Aug 19

The Curious Case of Exploding DecPOMDPs: Containing the Fire through Policy Counting

The paper introduces policy‑counted DecPOMDPs, a variant of decentralized partially observable Markov decision processes that mitigates the exponential growth in agent numbers by counting policies instead of agents. By exploiting symmetry among agents, the authors achieve a compact representation that reduces model complexity and evaluation cost to polynomial levels. They further present a dynamic programming algorithm that leverages this compact form to solve policy‑counted DecPOMDPs efficiently.

By Nazl{\i} Nur Karabulut, tanya Braun
arXiv AI
Sep 15

Delegating Authorization to Misaligned Agents: Coalitional Alignment and Safe Control

The paper studies how to safely delegate action approval to multiple AI reviewers when the reviewers themselves may be misaligned. It introduces a weaker condition—k‑robust coalitional alignment—under which a threshold rule that tolerates up to k disapprovals guarantees that the principal’s expected utility is at least as good as a baseline policy. The authors extend this characterization to sequential decision‑making in discounted MDPs and show that full‑panel coverage of reward functions ensures safety in Nash equilibria, while more permissive thresholds can lead to unsafe outcomes. Experiments demonstrate that collective review can remain sound even when individual reviewers are not fully aligned, provided some disapprovals are allowed.

By Natalie Collina, Surbhi Goel, Aaron Roth, Sikata Bela Sengupta