Riemann-bench
25 private research-mathematics problems from professors and IMO medalists. Agents with tools, 100 runs per problem.
- Made by
- Surge AI
- Released
- April 2026
- Kind
- Research mathematics
- Level
- Research frontier
- Scored
- Checked automatically
- Answers
- Short answer
- Tasks
- Kept private
- Strongest model tested
-
Gemini 4 Carbon #2 on the capability index
- Last in a launch post
- October 2026
- Last model added
- October 2026
- Scores refreshed
- November 12th, 2026
In the authors’ words
Recent AI systems have achieved gold-medal-level performance on the International Mathematical Olympiad, demonstrating remarkable proficiency at competition-style problem solving. However, competition mathematics represents only a narrow slice of mathematical reasoning: problems are drawn from limited domains, require minimal advanced machinery, and can often reward insightful tricks over deep theoretical knowledge. We introduce Riemann-Bench, a private benchmark of expert-curated problems designed to evaluate AI systems on research-level mathematics that goes far beyond the olympiad frontier. Problems are authored by Ivy League mathematics professors, graduate students, and PhD-holding IMO medalists, and routinely took their authors weeks to solve independently. Each problem undergoes double-blind verification by two independent domain experts who must solve the problem from scratch, and yields a unique, closed-form solution assessed by programmatic verifiers. We evaluate frontier models as unconstrained research agents, with full access to coding tools, search, and open-ended reasoning, using an unbiased statistical estimator computed over 100 independent runs per problem. Our results reveal that all frontier models currently score below 10%, exposing a substantial gap between olympiad-level problem solving and genuine research-level mathematical reasoning. By keeping the benchmark fully private, we ensure that measured performance reflects authentic mathematical capability rather than memorization of training data.
GPT-5.6 Sol leads with 83.2%
Best score per entry from the benchmark's own leaderboard, read on November 12th, 2026. Where a model ran with several settings or harnesses, we keep its best. Names in gray aren't in our model list: fine-tunes, agent systems, products and older models. They don't count toward leaders.
GPT-5.6 Sol leads with 83.2%, claims included
Best score per model from every source, including labs’ own numbers and claims Epoch AI collected from reports and papers. Labs pick their own settings, so a claim can beat an independent run of the same model.
- 83.2 GPT-5.6 Sol
- 81.6 GPT-6 Astra
- 80.0 Claude Opus 5.5
- 80.0
Gemini 4 Carbon
- 79.2 GPT-6.1 Sol
- 76.8 Claude Sonnet 5.5
- 74.4
Gemini 4 Argon
- 71.2 Claude Fable 5.1
- 63.2
Muse Wonder Full
- 60.8 Kimi K3.1 Pro
- 59.2 Muse Wonder 1.0
- 57.6 Grok 4.7
- 56.8
Gemini 3.8 Flash
- 53.6
Muse Spark 1.3
- 48.0
Qwen 3.8 Max
- 38.4
DeepSeek V4.1 Flash 1017
- 37.6 Beam 1.0
- 36.8 Kimi K3
- 24.0
Tencent Hy4 preview
- 20.8 GLM-5.3
- 20.0
Mistral Large 4
- 1 GPT-5.6 Sol max 83.2%
- 2 GPT-6 Astra max 81.6%
- 3 Claude Opus 5.5 adaptive/max 80%
- 4
Gemini 4 Carbon high 80%
- 5 GPT-6.1 Sol max 79.2%
- 6 Claude Sonnet 5.5 adaptive/max 76.8%
- 7
Gemini 4 Argon high 74.4%
- 8 Claude Fable 5.1 adaptive/max 71.2%
- 9
Muse Wonder Full max 63.2%
- 10 Kimi K3.1 Pro max 60.8%
- 11 Muse Wonder 1.0 max 59.2%
- 12 Grok 4.7 xhigh 57.6%
- 13
Gemini 3.8 Flash high 56.8%
- 14
Muse Spark 1.3 xhigh 53.6%
- 15
Qwen 3.8 Max xhigh 48%
- 16
DeepSeek V4.1 Flash 1017 max 38.4%
- 17 Beam 1.0 max 37.6%
- 18 Kimi K3 max 36.8%
- 19
Tencent Hy4 preview high 24%
- 20 GLM-5.3 max 20.8%
- 21
Mistral Large 4 high 20%
Source: Official Riemann-bench leaderboard
- 83.2 GPT-5.6 Sol
- 81.6 GPT-6 Astra
- 80.0 Claude Opus 5.5
- 80.0
Gemini 4 Carbon
- 79.2 GPT-6.1 Sol
- 76.8 Claude Sonnet 5.5
- 76.0
Gemini 4 Argon
- 71.2 Claude Fable 5.1
- 63.2
Muse Wonder Full
- 60.8 Kimi K3.1 Pro
- 60.0 Claude Opus 5
- 57.6 Grok 4.7
- 56.8
Gemini 3.8 Flash
- 55.0 Claude Fable 5
- 53.6
Muse Spark 1.3
- 48.0
Qwen 3.8 Max
- 38.4
DeepSeek V4.1 Flash 1017
- 37.6 Beam 1.0
- 36.8 Kimi K3
- 24.0
Tencent Hy4 preview
- 20.8 GLM-5.3
- 20.0
Mistral Large 4
- 1 GPT-5.6 Sol max 83.2%
- 2 GPT-6 Astra max 81.6%
- 3 Claude Opus 5.5 adaptive/max 80%
- 4
Gemini 4 Carbon high 80%
- 5 GPT-6.1 Sol max 79.2%
- 6 Claude Sonnet 5.5 adaptive/max 76.8%
- 7
Gemini 4 Argon 76%
- 8 Claude Fable 5.1 adaptive/max 71.2%
- 9
Muse Wonder Full max 63.2%
- 10 Kimi K3.1 Pro max 60.8%
- 11 Claude Opus 5 60%
- 12 Grok 4.7 xhigh 57.6%
- 13
Gemini 3.8 Flash high 56.8%
- 14 Claude Fable 5 55%
- 15
Muse Spark 1.3 xhigh 53.6%
- 16
Qwen 3.8 Max xhigh 48%
- 17
DeepSeek V4.1 Flash 1017 max 38.4%
- 18 Beam 1.0 max 37.6%
- 19 Kimi K3 max 36.8%
- 20
Tencent Hy4 preview high 24%
- 21 GLM-5.3 max 20.8%
- 22
Mistral Large 4 high 20%
Sources: Official Riemann-bench leaderboard and labs’ model cards
| # | Entry | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | GPT-5.6 Sol | 83.2% | max | Jul 2026 | Official leaderboard |
| 2 | GPT-6 Astra | 81.6% | max | Sep 2026 | Official leaderboard |
| 3 | Claude Opus 5.5 | 80% | adaptive/max | Sep 2026 | Official leaderboard |
| 4 | | 80% | high | Oct 2026 | Official leaderboard |
| 5 | GPT-6.1 Sol | 79.2% | max | Sep 2026 | Official leaderboard |
| 6 | Claude Sonnet 5.5 | 76.8% | adaptive/max | Sep 2026 | Official leaderboard |
| 7 | | 74.4% | high | Sep 2026 | Official leaderboard |
| 8 | Claude Fable 5.1 | 71.2% | adaptive/max | Sep 2026 | Official leaderboard |
| 9 | | 63.2% | max | Oct 2026 | Official leaderboard |
| 10 | Kimi K3.1 Pro | 60.8% | max | Oct 2026 | Official leaderboard |
| 11 | Muse Wonder 1.0 | 59.2% | max | Official leaderboard | |
| 12 | Grok 4.7 | 57.6% | xhigh | Sep 2026 | Official leaderboard |
| 13 | | 56.8% | high | Sep 2026 | Official leaderboard |
| 14 | | 53.6% | xhigh | Sep 2026 | Official leaderboard |
| 15 | | 48% | xhigh | Aug 2026 | Official leaderboard |
| 16 | | 38.4% | max | Oct 2026 | Official leaderboard |
| 17 | Beam 1.0 | 37.6% | max | Oct 2026 | Official leaderboard |
| 18 | Kimi K3 | 36.8% | max | Jul 2026 | Official leaderboard |
| 19 | | 24% | high | Aug 2026 | Official leaderboard |
| 20 | GLM-5.3 | 20.8% | max | Aug 2026 | Official leaderboard |
| 21 | | 20% | high | Oct 2026 | Official leaderboard |
| # | Model | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | GPT-5.6 Sol | 83.2% | max | Jul 2026 | Official leaderboard |
| 2 | GPT-6 Astra | 81.6% | max | Sep 2026 | Official leaderboard |
| 3 | Claude Opus 5.5 | 80% | adaptive/max | Sep 2026 | Official leaderboard |
| 4 | | 80% | high | Oct 2026 | Official leaderboard |
| 5 | GPT-6.1 Sol | 79.2% | max | Sep 2026 | Official leaderboard |
| 6 | Claude Sonnet 5.5 | 76.8% | adaptive/max | Sep 2026 | Official leaderboard |
| 7 | | 76% | Oct 2026 | Lab model card | |
| 8 | Claude Fable 5.1 | 71.2% | adaptive/max | Sep 2026 | Official leaderboard |
| 9 | | 63.2% | max | Oct 2026 | Official leaderboard |
| 10 | Kimi K3.1 Pro | 60.8% | max | Oct 2026 | Official leaderboard |
| 11 | Claude Opus 5 | 60% | Jul 2026 | Lab model card | |
| 12 | Grok 4.7 | 57.6% | xhigh | Sep 2026 | Official leaderboard |
| 13 | | 56.8% | high | Sep 2026 | Official leaderboard |
| 14 | Claude Fable 5 | 55% | Jun 2026 | Lab model card | |
| 15 | | 53.6% | xhigh | Sep 2026 | Official leaderboard |
| 16 | | 48% | xhigh | Aug 2026 | Official leaderboard |
| 17 | | 38.4% | max | Oct 2026 | Official leaderboard |
| 18 | Beam 1.0 | 37.6% | max | Oct 2026 | Official leaderboard |
| 19 | Kimi K3 | 36.8% | max | Jul 2026 | Official leaderboard |
| 20 | | 24% | high | Aug 2026 | Official leaderboard |
| 21 | GLM-5.3 | 20.8% | max | Aug 2026 | Official leaderboard |
| 22 | | 20% | high | Oct 2026 | Official leaderboard |
Labs report scores for 4 models in their cards. Switch the scores above to rank them together.
Number one over time 2 models have held number one with claims included since its release in April 2026
Lab claims count from the day the card came out, independent runs from the model’s release. We draw one row each for the benchmark’s own leaderboard and what labs claim in their cards.
Sources: Official Riemann-bench leaderboard and labs’ model cards
Scores over time
All the scores we have, one dot each, so a model tested at several settings appears more than once.
Sources: Official Riemann-bench leaderboard and labs’ model cards
2 labs put it in a launch post in the last six months
Launch posts from every lab that has listed it, one tick per post. Tall colored ticks include it, and short gray ones leave it out.
| Date | Launch post | Score | As the post writes it |
|---|---|---|---|
| Oct 28, 2026 | 80 | RiemannBench | |
| Oct 13, 2026 | 76 | RiemannBench | |
| Jun 9, 2026 | Claude Fable 5 | 55 | RiemannBench |
2 system cards report it, from 2 labs
Besides launch posts, we read the system cards, model cards and technical reports labs publish with a release. They report far more, including safety and frontier-risk tests.
| Date | Document | Score | As the document writes it | Section |
|---|---|---|---|---|
| Oct 13, 2026 | | 76 | RiemannBench (results table, p.5) | Capabilities |
| Jul 24, 2026 | Claude Opus 5 system card | 60 | RiemannBench, max effort without tools, mean of 4 attempts (79% with tools), printed on chart (8.7, Figure 8.7.A) | Capabilities |
2 lab claims next to the leaderboard
Each score a lab reported for its own model, beside the same model's best score on the leaderboard. Gaps mostly come from different harnesses, effort levels and task subsets. 1 of them match, which usually means one side copied the other. Every benchmark.
| Model | Lab says | Board says | Gap |
|---|---|---|---|
| | 76% RiemannBench | 74.4% Leaderboard, high | +1.6 pts |
| | 80% RiemannBench | 80% Leaderboard, high | Same |
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