Leanstral 1.5: Proof Abundance for All
Summary
Mistral AI has released Leanstral 1.5, an open source model that significantly improves formal verification and mathematical proof performance using the Lean 4 language.
Key Points
- Leanstral 1.5 is a free, open source model under the Apache-2.0 license that uses 6B active parameters out of a total of 119B parameters.
- It was trained through a three-stage process of intermediate training, supervised fine tuning (SFT), and CISPO-based reinforcement learning (RL), and utilized a multi-turn and code agent environment.
- During the actual open source repository verification process, we found five errors that had not previously been found, proving the applicability in practice.
Notable Quotes & Details
Notable Data / Quotes
- 119B total and only 6B active parameters
- 587/672 PutnamBench
- FATE-H (87%)
- FATE-X (34%)
- 5 previously unknown bugs across 57 repositories
Intended Audience
Formal Verification researcher, developer in the fields of mathematical proof and software reliability engineering