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A unanimous verifier panel gates every proof in Nvidia's IMO gold recipe
Nvidia's Nemotron scored 30 of 42 at IMO 2026 writing proofs in ordinary prose, and the September 9 paper publishes the data, the code and the acceptance rule that decided which candidate proofs survived.
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What happened
- Nvidia posted a paper to arXiv on 9 September 2026 describing a Nemotron system that scored 30 of 42 points at IMO 2026, past the 29-point gold threshold.
- The system ran in pure natural language with no formal prover, no external mathematical tools and no internet, unlike AlphaProof, DeepSeekProver, GoedelProver and SeedProver, which check each step in Lean or another formal environment.
- It took full marks on problems 1, 2, 4 and 5 and partial credit on 3 and 6, and an informal re-check after the contest, against proofs found later, moved the total to 33.
- The paper releases five artifacts: two trained checkpoints, the training data, the training and inference code, the answers actually submitted at the competition, and Nemotron-IMO-Bench.
Compiled by The EngineerSomething wrong?How this is made
Why it matters
- constraint Requiring unanimous top marks from the panel throws away correct proofs that one verifier dislikes, so the candidate volume a team must generate per problem tracks the strictness of the gate more than the difficulty of the problem.
- cost The gate on reproducing this is compute, not access: a 550B-A55B-class base, generation runs capped at 400,000 tokens, and RL batches of 2,048 trajectories are what a team has to fund after downloading the recipe.
- exposure Anyone citing 30/42 in a procurement deck is citing the team's own marking of its own natural-language proofs, in a pipeline whose paper admits a verifier can bless a wrong argument.
- precedent Publishing the submitted answers makes outside re-marking possible. The Fields medallists' complaint about hasty announcements implies the same bar for the next claimed olympiad result.
A proof clears the search only when every verifier on the panel calls it valid and all of them award the top correctness score at the same time [10]. One objection sends the candidate back for revision. The panel's average score is not the criterion [10]. The account here comes from the paper by way of a dev.to post credited to Nokka and dated 14 September 2026. The post says the text was drafted by a language model and checked and edited by hand [1].
Each verifier on the panel is a different model. Nvidia splits three checkpoints out of Nemotron 3 Ultra 550B-A55B and treats them as complementary sources of mathematical behaviour, without assuming the strongest single model is enough [13]. The stated reason for the split is practical. A model that writes good proofs may be worse at spotting small defects, and a verifier cheap enough to filter a large pile is too generous for the final call [11]. So the pipeline runs different checkpoints and different decision policies at different stages. The wrapper is a loop that generates candidates, verifies them, sends the rejected ones back with critique, and then compares the survivors in a separate selection step [12][9].
The supervised set began with 15,879 hard proof problems drawn from the AoPS portion of Nemotron-Math-Proofs-v1, chosen on earlier pass-rate measurements so the model trained on problems it was failing [14]. External models wrote several solutions per problem, each output allowed to run to 400,000 tokens, with up to three refinement rounds when a solution came back incomplete [15]. Another set of models labelled correctness 0, 0.5 or 1, and a meta-verification step scored how much to trust that label [16]. After malformed, empty, incomplete and over-length outputs were dropped, 414,890 examples survived, from 15,818 unique problems [17].
That works out to roughly 26 retained samples per problem [1], and 61 of the selected problems left nothing behind [2]. At the cap, those 414,890 samples top out near 166 billion tokens of retained generation [3], before anything that was filtered out. The reinforcement stage kept problems the base model solved one to three times out of four according to an external judge [18]. It used the DeepSeekMath-V2 framework with the self-analysis reward removed, at 128 problems times 16 trajectories per batch, or 2,048 trajectories [19].
The 30 sits one point above the 29-point gold line [4], and the post notes the figure is the team's own report, with no independent committee score in this setting [23]. The paper concedes that its verifiers can agree with an incorrect argument [8]. For the number to hold, an outside grader has to read the released submissions and reach the same marks. The informal re-check that lifted the total to 33 is one run of that process, done with proofs found after the contest [5].
Two days after the paper went up, 25 Fields medallists said that AI companies rushing to solve mathematics problems for use as benchmarks is harmful to mathematical science [21]. Their objection was to the process, according to the statement: answers announced in a hurry, with no time left to write them up cleanly, separate out the new methods, and cite prior work [22].
What to watch
- An independent regrade of the released contest submissions, which would either confirm 30/42 or move it in one direction.
- Whether the two released checkpoints are enough to stand up the full three-model verifier panel the search used.
- Whether any outside team reruns the RL stage at 128 problems by 16 trajectories and reports the score it gets.