Core Insights - The article discusses the potential of a new framework called SIHD (Structural Information-based Hierarchical Diffusion) for offline reinforcement learning, which adapts to various tasks by analyzing embedded structural information in offline trajectories [2][3][23]. Research Background and Motivation - Offline reinforcement learning aims to train effective policies using fixed historical datasets without new interactions with the environment. The introduction of diffusion models helps mitigate extrapolation errors caused by out-of-distribution states and actions [3][4]. - Current methods face limitations due to fixed hierarchical structures and single time scales, which hinder adaptability to different task complexities and decision-making flexibility [5][6]. SIHD Framework Core Design - SIHD innovates in three areas: hierarchical construction, conditional diffusion, and regularization exploration [5]. - The framework's hierarchical construction is adaptive, allowing the data's inherent structure to dictate the hierarchy [7][9]. - The conditional diffusion model uses structural information gain as a guiding signal, enhancing stability and robustness compared to traditional methods reliant on sparse reward signals [10][11]. - A structural entropy regularizer is introduced to encourage exploration and mitigate extrapolation errors, balancing exploration and exploitation in the training objective [12][13]. Experimental Results and Analysis - SIHD was evaluated on the D4RL benchmark, demonstrating superior performance in standard offline RL tasks and long-horizon navigation tasks [14][15]. - In Gym-MuJoCo tasks, SIHD achieved optimal average returns across various data quality levels, outperforming advanced hierarchical baselines with average improvements of 3.8% and 3.9% in medium-quality datasets [16][17][18]. - In long-horizon navigation tasks, SIHD showed significant advantages, particularly in sparse reward scenarios, with notable performance improvements in Maze2D and AntMaze tasks [19][20][22]. - Ablation studies confirmed the necessity of SIHD's components, especially the adaptive multi-scale hierarchy, which is crucial for performance in long-horizon tasks [21][22]. Conclusion - The SIHD framework successfully constructs an adaptive multi-scale hierarchical diffusion model, overcoming rigid limitations of existing methods and significantly enhancing offline policy learning performance, generalization, and robustness [23]. Future research may explore more refined sub-goal conditional strategies and extend SIHD's concepts to broader diffusion-based generative models [23].