When two objectives conflict, training one policy per preference wastes data, so this routes between a small set instead
AspireAI community · arXiv
Multi-objective reinforcement learning has to balance competing objectives, such as helpfulness against honesty in safety work, or speed against energy in robotics, and the optimal policy can shift sharply with the objective weighting, which makes per-preference policy learning sample-inefficient. This paper introduces objective-conflict coefficients and derives near-optimal regret bounds for online settings using them, then designs routed ensemble policy learning, which keeps a small set of basis policies and dynamically routes trajectories to the one with the highest potential reward, plus a kernel surrogate trajectory attribution algorithm that estimates how feedback on one trajectory influences learning on others, capturing nonlinear synergy and antagonism. Routed ensembles improve average performance by 4.3% over baselines on Meta-World and MO-Gymnasium, attribution correlation with leave-one-out analysis improves by 50%, and applying attribution to trajectory selection yields 27% higher reward. An extended version appears at NeurIPS 2026.
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Two sparse-autoencoder analyses have resisted scaling: matching semantically similar features across layers, and compressing large feature circuits into interpretable supernodes. This paper argues both are the same underlying problem, estimating semantic distances between SAE features that sit on different activation manifolds. Its representation treats each feature not as a single decoder vector but as an activation-weighted distribution over the hidden states expressing it, projects those distributions into a shared reference space, and compares them with Wasserstein distance. The representation is proved invariant to activation rescaling and stable under perturbation, and recovers true matches under finite-sample margin conditions. Empirically it outperformed decoder-vector and LLM-based baselines and captured subtle functional distinctions between related features, and it compressed large feature circuits into interpretable supernodes automatically. The limitation is that this is interpretability tooling: the paper demonstrates better feature matching and circuit compression, not that downstream interpretability claims become more accurate.