arXiv AI

Conservative Policy Iteration For Zero-Sum POSGs

The paper introduces an approximate policy‑iteration algorithm for finite‑horizon zero‑sum partially observable stochastic games (zs‑POSGs). It maintains a separate policy for each player and updates both jointly using conservative policy updates along occupancy trajectories, avoiding the need to approximate a full central value function. The method focuses computation on occupancy regions where the current joint policy can be exploited, and shows competitive performance on small horizons while improving the runtime‑exploitability trade‑off at larger horizons compared to existing solvers such as PBVI, HSVI, and CFR+.

arXiv Machine Learning
Oct 21

Planning under Noise with Neural Operators

The paper introduces Planning Under Noise (PUN), a neural operator that learns noise‑aware value fields for planning in unseen geometries. By imposing reflecting Neumann conditions on obstacles and a Dirichlet condition at the goal, PUN allows sampled paths to explore free space until reaching the target. It extends the Monte Carlo solver Walk on Stars to higher dimensions, learns geometry‑to‑field mappings from noisy labels, and achieves high success rates and low runtimes on 4‑D replanning benchmarks across multiple noise levels.

By Michael Chen, Hong Chul Nam, Xi Deng, Anima Anandkumar
arXiv AI
Jun 24

EMAgnet: Parameter-Space EMA Regularization for Policy Gradient Self-Play in Large Games

arXiv:2606. 23995v1 Announce Type: cross Abstract: Recent work has established that regularized policy gradient methods such as PPO, when used in self-play, can match or exceed specialized game-theoretic algorithms for solving two-player zero-sum imperfect-information games.

By Tristan Maidment, JB Lanier, Chase McDonald, Nathan Tsang, Eugene Vinitsky, Roy Fox, Albert Wang, Wesley N. Kerr
arXiv Machine Learning
Sep 2

NashDreamer: Model-Based Reinforcement Learning for Zero-Sum Imperfect-Information Games

NashDreamer is a new model-based reinforcement learning framework designed for two-player zero-sum imperfect-information games. It introduces a centralized Multi-Agent Recurrent State-Space Model that separates environment dynamics from player strategy effects, enabling the use of any policy gradient algorithm while preserving convergence guarantees to Nash equilibria. Experiments on four benchmark games show that NashDreamer achieves significantly better sample efficiency than model-free baselines early in training, and the authors analyze its optimization landscape, noting a potential vulnerability to posterior collapse in stochastic settings.

By Tom\'a\v{s} Hole\v{c}ek, Viliam Lis\'y