aspireai.
PUBLIC EDITION

Meta's FAIR team built a bare-bones Lean harness and it matched specialised theorem-proving workflows at the same model

AspireAI community · arXiv (Meta FAIR)
*A simple agentic loop, given an efficient Lean 4 interface and verifier feedback, matched or beat specialised theorem-proving workflows at the same model.* The h1 harness gives the model a direct Lean interface and keeps it working through verifier feedback and self-reflection, without imposing any decomposition or search structure. It reaches state-of-the-art results on PutnamBench, FATE-X and FormalConjectures100-Solved, and settles eight open problems in FormalConjectures. The authors compared against Goedel-Architect and AlphaProof Nexus at matched models, and found h1 matched or outperformed them, with a single attempt (pass@1) often enough to solve open problems. The ablations add the caveat that matters: simplicity alone is not enough - an efficient Lean interface largely determines cost and solve rate. The paper recommends that future work evaluate frontier models with efficient execution feedback before prescribing workflows.
Read the story and explore more from the AspireAI community.
Discover more stories
Stay curious.
THE BIG PICTURE
A FRESH PERSPECTIVE
Research
One distance function matched sparse-autoencoder features across layers and compressed feature circuits into supernodes
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.
Swipe into something new
01 / 1729
The conversation continues
Explore Builds — projects by Kiran Adimatyam ↗
A fresh perspective changes everything.
ASPIREAI — STAY CURIOUS.