# A Mathematician Used Claude Fable to Disprove the 87-Year-Old Jacobian Conjecture in a Few Hours

> **Open Intelligence Dossier** · First detected: 2026-07-20 21:07 UTC · Category: Technology

## Executive Summary
A mathematician has reportedly used Anthropic's Claude Fable 5 to disprove the Jacobian conjecture, a mathematical riddle that has remained unsolved since 1939.

## Intelligence Brief
A mathematician has claimed to disprove the Jacobian conjecture, a significant mathematical problem that has persisted for 87 years. This breakthrough was achieved using Claude Fable 5, an AI model developed by Anthropic. According to reports from Glitchwire and Mashable, the process of disproving the conjecture took only a few hours. The methodology involved the AI finding a counterexample to the conjecture, which had remained an open riddle in the field of mathematics since its origin in 1939. Coverage of this event is being reported across several outlets, including New Scientist and ForkLog.


New Scientist notes that the AI's solution to the riddle has taken mathematicians by surprise. Further details provided by Inshorts indicate that the mathematician's claims involve the use of Claude Fable to facilitate the disproof. Additionally, Inshorts mentions that Alpöge's function has also output three new numbers as part of the associated mathematical developments surrounding this event. To understand the significance of this event, it is necessary to note that the Jacobian conjecture dates back to 1939. For 87 years, the mathematical community has sought to prove or disprove this specific conjecture.


The introduction of Claude Fable 5 as a tool for discovery suggests a shift in how long-standing mathematical problems are approached, moving from traditional manual proofs to AI-assisted counterexample searches that can be completed in a matter of hours. Future attention will likely focus on the verification of the counterexample provided by Claude Fable 5. Because the mathematician claims the AI helped disprove the conjecture, the academic community must now validate the specific outputs and the role of Alpöge's function in generating the three new numbers. Coverage does not yet specify the identity of the mathematician or the peer-review status of the findings, but the speed of the discovery remains a primary point of interest for the reporting outlets.

## Multi-Source Evidence Table
| Source Outlet | Headline | Verification URL |
|---|---|---|
| Mashable | A mathematician used Fable 5 to disprove a major math problem | [Source Link](https://news.google.com/rss/articles/CBMifkFVX3lxTE5kQzdTMmg0WENCaFNRcmp0T0xFdWpqSEtmWTV5WDlYbVlFRDVmRDcya0lnT080VWdFMktYSWFDYzkzTWhoeEFEN3RQNHRBSFk0cmxlTkl6Y2s0eDVyd0d1Y2FxekQ2dWV5dmUyU25pb0c1TEs5UHlLRHlGTlBwZw?oc=5) |
| ForkLog | Anthropic’s Claude Fable 5 finds counterexample to 1939 Jacobian conjecture | [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 - Inshorts | [Source Link](https://news.google.com/rss/articles/CBMixwFBVV95cUxNOVVyRVhsMFZMWEdNdXVjQ1diaGVlV092bEhHTGZHWlRjZmpaV3paRjh3MDJjTzh0SlNEUWp5ZHVvUUQ5QWpOQUk5VnpyOGlHdERrWjVTdXZ4WWYxV3MxM3hXaXkwcEltb1hXM3JJMkJaWW9peTdCZ0lIU190Q2V1Q2h2ZHZUT2RPN2V5N2M4a01Ld3ZwZFdiSmljWjhwMzQxTkk5NGFBcWVmWFhDc252YUJBWU9lVjNIZ0JocDZ1RXFXM0hhNkY40gHMAUFVX3lxTE1SU3IxTDVqRVlXSHV0Ym1rNmJhX2llN3FuRWxSMElJYjN0ZUljcXBDaUk4cEQ1dkVuNkdYejkwUW54RVk0MDU1cDZNeVdBN2hubFl3dFZYZEpBTU1NSUY4ajluLUJJYXNOaGhZUGprOExsc2RUN212dkJJS1JLZ3hJc1dVZEFqdUZNSTB) |
| New Scientist | AI’s solution to 87-year-old riddle takes mathematicians by surprise | [Source Link](https://news.google.com/rss/articles/CBMiswFBVV95cUxQSF9LQzI4Um5hRDJXdFNQbEJrNDJMSmcyNzBkU0lHYUFGZDljNXk4Q290ZWV3WEUwZUpySDJyS05BMW4tYnd2bGV4UFVGVFNybUxEQXZOVTd5RTBWNllMdjJ0OEVZM25nMkJFWS1mblFXMkpZb2lqUmFrY1g4VGUyTDA1T0F6ZU83ZlQ5YlkyRWpUVWU0RGhtVi1QYTgxb2ZvSEh0bnRrQWRqazdfVm1CVWNKaw?oc=5) |
| Glitchwire | A Mathematician Used Claude Fable to Disprove the 87-Year-Old Jacobian Conjecture in a Few Hours | [Source Link](https://news.google.com/rss/articles/CBMirgFBVV95cUxPR3FkbWFVLUsxeGsyZEVIV1luYm9oa2pZTzB6WjhWbHlsQzhZQTgxSTZ1MmgtU0FZY3VCckFmWHNMVzhtQTVwck80Vmh6WjZDdmhUWU1MaVFudDhqTXR0Vk9qdjRLZjhfYktsZWFyYlh3eUZLLUdZTVR4XzBHMUhxTkloT2NNcXNaYjRVdFdmTG1XWUJOZHZxZkdNSWJ5VWVtZGN0WkJsZHJadWtZMXc?oc=5) |

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