# A mathematician used Fable 5 to disprove a major math problem

> **Newsylist Open Intelligence Dossier** · First detected: 2026-07-21 03:29 UTC · Category: Technology · Sources: 7 · Current Velocity: 9.92

## Executive Summary
A mathematician used Anthropic’s Claude Fable 5 to disprove the 87-year-old Jacobian conjecture in a matter of hours.

## Intelligence Brief
A mathematician has claimed to disprove the Jacobian conjecture, a mathematical riddle dating back to 1939. The process involved using the AI model Claude Fable 5 to find a counterexample.


Coverage from New Scientist, Mashable, and Glitchwire emphasizes that the solution took only a few hours and took the mathematical community by surprise. ForkLog specifies that the AI identified the counterexample, while Inshorts reports that Alpöge's function also output three new numbers.


Future attention will likely focus on the verification of the claim and the implications of the three new numbers generated by Alpöge's function.

## Verified Facts & Key Claims
### Which AI model was used to solve the problem?
The mathematician used Anthropic's Claude Fable 5.

### What is the Jacobian conjecture?
It is a major math problem and riddle that has remained unsolved for 87 years, originating in 1939.

### How long did it take to find the counterexample?
According to Glitchwire, the conjecture was disproven in a few hours.

## Key People, Organizations & Locations
Fable, Claude Fable, Jacobian, Mathematician, Alpöge, A Mathematician Used Claude Fable, Disprove, Jacobian Conjecture

## Multi-Source Evidence Table
| Source Outlet | Headline | Published (UTC) | Verification URL |
|---|---|---|---|
| GIGAZINE | Anthropic researchers report that the AI 'Claude Fable 5' has generated a counterexample that overturns the Jacobian conjecture, a problem that has been unsolved for 87 years. | 2026-07-21 04:51 | [Source Link](https://news.google.com/rss/articles/CBMigwFBVV95cUxPN3p5WnpJRk9XSjZ1ei1RYjI4bWRMNWs4TmZjTHFTZjFBeFV1eFE4Szg0cW92ZXMwaTkwREFqb2k3aFdDb1lBd2xxa0RGUHpzRExOVkpIaC16cTEwLU1yTzRPRGlnTFgxa09FNEJQaXpOYkJnZUlVTHN0MVNkWGdjUUQxcw?oc=5) |
| KuCoin | Fable 5 Refutes the 87-Year-Old Jacobian Conjecture, Shaking the Mathematics Community | 2026-07-21 04:51 | [Source Link](https://news.google.com/rss/articles/CBMiqgFBVV95cUxORHVYQ243MDRIVzRkYVo1QnJjUWd5LXJqTko4UzhjdWFBMG51ajdVa0xqMjVEYUNZeVpiSC1qOWtYWXJhck5Mbl9DNzE1Tm53TkNGcFBhdmg0a0w5OXpfX0NOblh6R29tTWdlYjFpYm9mNUlOdVVQOXBmOWFBZ2NSN2dZRVUxS0J3ckxzOUZyV0NaSTljZzVFU2k2M3VTZHdIUHRjWU1ET1B1QQ?oc=5) |
| ForkLog | Anthropic’s Claude Fable 5 finds counterexample to 1939 Jacobian conjecture | 2026-07-20 23:44 | [Source Link](https://news.google.com/rss/articles/CBMinwFBVV95cUxQMnJ2S0RsNDBBMElvWVBDRzR4aEVKdmxBSjN0d1V4c2NMdUR2QVlHOFFJaWlXeGV1eF9vVHc5aC1mWFd0M0N6T3BqaUxOdjlQTnVFVEJJY29qSzRzR3VzR251QjN6MVRRbGhoSWJLR1V3MWVsRXdpY0hvZkFFRERCYm1tZzZPdW9aSWUyN1BLRGFtMzczTjVPNFZLQVlnUTg?oc=5) |
| Inshorts | Mathematician claims Claude Fable helped him disprove 87-year-old Jacobian conjecture - Alpöge's function also outputs 3 new numbers | 2026-07-20 23:44 | [Source Link](https://news.google.com/rss/articles/CBMixwFBVV95cUxNOVVyRVhsMFZMWEdNdXVjQ1diaGVlV092bEhHTGZHWlRjZmpaV3paRjh3MDJjTzh0SlNEUWp5ZHVvUUQ5QWpOQUk5VnpyOGlHdERrWjVTdXZ4WWYxV3MxM3hXaXkwcEltb1hXM3JJMkJaWW9peTdCZ0lIU190Q2V1Q2h2ZHZUT2RPN2V5N2M4a01Ld3ZwZFdiSmljWjhwMzQxTkk5NGFBcWVmWFhDc252YUJBWU9lVjNIZ0JocDZ1RXFXM0hhNkY40gHMAUFVX3lxTE1SU3IxTDVqRVlXSHV0Ym1rNmJhX2llN3FuRWxSMElJYjN0ZUljcXBDaUk4cEQ1dkVuNkdYejkwUW54RVk0MDU1cDZNeVdBN2hubFl3dFZYZEpBTU1NSUY4ajluLUJJYXNOaGhZUGprOExsc2RUN212dkJJS1JLZ3hJc1dVZEFqdUZNSTB) |
| Glitchwire | A Mathematician Used Claude Fable to Disprove the 87-Year-Old Jacobian Conjecture in a Few Hours | 2026-07-20 23:44 | [Source Link](https://news.google.com/rss/articles/CBMirgFBVV95cUxPR3FkbWFVLUsxeGsyZEVIV1luYm9oa2pZTzB6WjhWbHlsQzhZQTgxSTZ1MmgtU0FZY3VCckFmWHNMVzhtQTVwck80Vmh6WjZDdmhUWU1MaVFudDhqTXR0Vk9qdjRLZjhfYktsZWFyYlh3eUZLLUdZTVR4XzBHMUhxTkloT2NNcXNaYjRVdFdmTG1XWUJOZHZxZkdNSWJ5VWVtZGN0WkJsZHJadWtZMXc?oc=5) |
| New Scientist | AI’s solution to 87-year-old riddle takes mathematicians by surprise | 2026-07-20 23:44 | [Source Link](https://news.google.com/rss/articles/CBMiswFBVV95cUxQSF9LQzI4Um5hRDJXdFNQbEJrNDJMSmcyNzBkU0lHYUFGZDljNXk4Q290ZWV3WEUwZUpySDJyS05BMW4tYnd2bGV4UFVGVFNybUxEQXZOVTd5RTBWNllMdjJ0OEVZM25nMkJFWS1mblFXMkpZb2lqUmFrY1g4VGUyTDA1T0F6ZU83ZlQ5YlkyRWpUVWU0RGhtVi1QYTgxb2ZvSEh0bnRrQWRqazdfVm1CVWNKaw?oc=5) |
| Mashable | A mathematician used Fable 5 to disprove a major math problem | 2026-07-20 23:44 | [Source Link](https://news.google.com/rss/articles/CBMifkFVX3lxTE5kQzdTMmg0WENCaFNRcmp0T0xFdWpqSEtmWTV5WDlYbVlFRDVmRDcya0lnT080VWdFMktYSWFDYzkzTWhoeEFEN3RQNHRBSFk0cmxlTkl6Y2s0eDVyd0d1Y2FxekQ2dWV5dmUyU25pb0c1TEs5UHlLRHlGTlBwZw?oc=5) |

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