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# Aletheia scored 91.9% on IMO-ProofBench olympiad proofs in early 2026, against 7.1% for GPT-5.1
- URL: https://aiadoption.org/data/imo-proofbench-proof-scores/
- Published: 2026-10-19T16:06:30.000Z
- Updated: 2026-10-21T06:00:55.000Z
- Description: On IMO-ProofBench, which grades step-by-step proofs for 60 olympiad-style problems, Aletheia scored 91.9% and Gemini 3 Deep Think 76.7%. GPT-5.1 scored 7.1%, a spread of 84.8 percentage points.
- Author: Manu
- Tags: Data, AI Benchmarks, Large Language Models, #chart, #ai-index-2026, #hub-benchmarks

91.9%

#1 of 9

IMO-ProofBench score of Aletheia, the highest of nine systems; Gemini 3 Deep Think scored 76.7%

Aletheia91.9%

Gemini 3 Deep Think76.7%

GPT-5.17.1%

## What the chart shows

IMO-ProofBench asks AI systems to write full, rigorous proofs for 60 problems ranging from pre-olympiad to International Mathematical Olympiad level. Aletheia led at 91.9%, followed by Gemini 3 Deep Think (76.7%) and the Gemini Deep Think version that won gold at the 2025 olympiad (65.7%).

Scores then drop: GPT-5.2 Thinking (high) reached 35.7%, Gemini 3 Pro 30% and GPT-5.1 7.1%, a spread of 84.8 percentage points. The AI Index notes that most models are far better at reaching correct answers than at proving them.

## Key numbers

| Measure                      | Value |
| ---------------------------- | ----- |
| Aletheia                     | 91.9% |
| Gemini 3 Deep Think          | 76.7% |
| Gemini Deep Think (IMO Gold) | 65.7% |
| GPT-5.2 Thinking (high)      | 35.7% |
| Gemini 3 Pro                 | 30.0% |
| GPT-5.1                      | 7.1%  |

## How to read it

- The benchmark’s authors validated automated proof grading against human experts, but recommend human checks for high-stakes results.
- “Gemini Deep Think (IMO Gold)” is the version that solved five of six problems at the 2025 International Mathematical Olympiad.
- A breakdown in the IMO-Bench paper suggests some scores may partly reflect familiarity with past competition problems.

**Source:** [IMO-ProofBench Leaderboard](https://aiadoption.org/sources/#imo-proofbench), 2026, via the AI Index Report 2026 (Stanford HAI), figure 2.5.7: *IMO-ProofBench*. Chart and text by AI Adoption.  
Numbers checked against the published data on 20 October 2026.  
[Download the data (CSV)](https://charts.aiadoption.org/ai-index/csv/imo-proofbench-proof-scores.csv?ref=aiadoption.org) · [Cite this chart](#source)