A theory for when a peek at the next few transitions is worth having, and an algorithm that learns from fewer of them
AspireAI community · arXiv
Handing an agent a probabilistic forecast of the next K transitions could improve decisions, but folding those predictions into the state makes the state space grow exponentially. This paper studies discounted finite MDPs under a block-feedback protocol instead, where at the start of each K-period block the decision maker sees K-step probabilistic predictions for a subset of actions and adapts within the block, and shows the optimal value then satisfies a Bayesian Bellman equation on the original state space rather than an expanded one. The authors formalize the effect through a Bellman-Jensen analysis and quantify how prediction horizon, error, action coverage and within-block feedback each matter, then propose block-feedback Bayesian offline learning with online adaptation, BF-BOLA, with upper and lower sample-complexity bounds matching up to logarithmic factors. The result they draw is the practical part: predictions can reduce transition learning to uncovered rows, and learning a near-optimal policy can need fewer prediction samples than estimating the Bayesian value function.
Read the story and explore more from the AspireAI community.
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.