Mistral AI's Leanstral 1.5 is a free, open-weights Lean 4 theorem-proving model saturating miniF2F, with 6.5B active parameters.

Mistral AI's Leanstral 1.5 is a free, open-weights Lean 4 theorem-proving model saturating miniF2F, with 6.5B active parameters.

Mistral AI released Leanstral 1.5, an open-source model for formal verification in Lean 4. Beyond math, the model found five previously unknown bugs while scanning 57 open-source…