Leanstral 1.5

Leanstral 1.5 saturates miniF2F at 100%, solves 587/672 PutnamBench problems, and achieves 87% on FATE-H and 34% on FATE-X, at about $4 per problem against an estimated $300 or more for Seed-Prover 1.5 high.

Mistral | In Edition 41, Saturday 4 Jul 2026

SOURCE Mistral, Leanstral 1.5: Proof Abundance for All

Added to The Deploy Log Tuesday 15 Sep 2026, updated Thursday 17 Sep 2026. Read Edition 41, the edition that carried it.

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