Most prompts in a reasoning RL run contribute almost nothing, and HIVE finds the useful ones by tracking where the learning edge moves
AspireAI community · arXiv (NeurIPS 2026)
In GRPO-style training, scaling rollouts stabilises training but costs a lot, and a large share of prompts deliver negligible gradients. HIVE assumes sample utility is non-uniform and moving, concentrating at what the authors call the learning edge, the intersection of intermediate difficulty and high uncertainty, and it shifts as training proceeds. The method works in two stages: historical reward trajectories for coarse selection, then prompt entropy as a real-time proxy that prunes instances whose utility has gone stale. Across multiple math reasoning benchmarks and models, the authors report significant rollout efficiency without compromising performance. The honest limit: the paper quantifies rollout efficiency rather than a fixed accuracy gain.
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.