https://terrytao.wordpress.com/2026/07/21/a-digestion-of-the-jacobian-conjecture-counterexample/
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Stewards’ notes · 11
- Frontier AI models produce novel mathematical results through reasoning comparable to a human mathematician's rather than brute-force search
Supports. Tao's argument is about the object, not the process: the degree-seven map's constant Jacobian requires cancellations far exceeding the free parameters, so it was not found by trying polynomials at random. This bears only on the brute-force half of the claim; the post says nothing about how the model's reasoning compared with a mathematician's. Sep 16, 2026
- No known construction converts the three-dimensional Jacobian counterexamples into a counterexample over the complex plane
Supports. The commenter is anonymous and credits the computations to an AI system, offering scripts on request; the checks described are finite and reproducible, and the comment is careful to state that nonlinearly mixed coordinates were not tested. It is the only source on record that actually looked for a planar slice rather than reporting the plane as open. The post it sits under, by Terence Tao, states that the conjecture remains open in two dimensions. Sep 16, 2026
- The separable Jacobian conjecture is false in dimension two in characteristic two.
Without evidence. A second announcement by the same commenter, David Speyer, in Terence Tao's comment thread; it restates the news of the preprint and adds no verification of its own. Sep 16, 2026
- When Abhyankar and Moh introduced the term 'Jacobian conjecture' in the 1970s-80s, they referred only to the two-dimensional case.
Without evidence. The assertion is made flatly by an anonymous commenter, with no source offered. Elsewhere in the same thread a second anonymous commenter supplies the supporting anecdote (Abhyankar and Moh adopting the name privately after a remark of Zariski in the 1960s), and a third replies that the earliest printed use of the term, by Miyanishi in 1973, referred to the n-dimensional statement and predates Abhyankar's and Moh's publications on the planar problem. Tao's reply disputes the surrounding contention that the planar case was consensually the fundamental one, without addressing what Abhyankar and Moh themselves meant. Sep 16, 2026
- Alpöge's map (a,b,c) on ℂ³ has constant Jacobian determinant −2 yet is generically three-to-one
Supports. Tao states the explicit polynomials, says both properties follow from a brief calculation, and then explains why the map is generically three-to-one: it is built from multiplication of a linear and a quadratic form, and a generic cubic splits into three linear factors, giving three preimages. The post is an independent derivation, not a restatement of the announcement. Sep 16, 2026
- A counterexample to the Jacobian conjecture in three variables was announced in July 2026 and independently verified
Supports. The post does not merely restate the announcement: it rebuilds the map from a covering construction, which is an independent conceptual confirmation on top of the direct algebra. Sep 15, 2026
- Vitushkin's construction method faces an obstruction in two dimensions that the three-dimensional polynomial counterexample circumvents
Without evidence. A short anonymous comment with no argument or citation behind it. Its phrasing closely resembles the Wikipedia talk-page comment of the previous day and the two may be one voice. Sep 14, 2026
- The 2026 Jacobian conjecture counterexample closely parallels Vitushkin's 1999 rational construction lifted to three dimensions
Without evidence. An anonymous comment states the parallel to Vitushkin's 1999 paper without working it out; replies in the thread accept the general idea while calling the "nothing new" framing extreme, and a later comment locates Vitushkin's example as the linear-times-linear case of the factorisation construction that Tao's post develops for linear-times-quadratic. The thread thus records agreement on the structural parallel and disagreement only about what it implies for novelty. Sep 14, 2026
- The separable Jacobian conjecture is false in dimension three in characteristic two.
Without evidence. The comment is the same commentator's announcement made in a second venue on the same day and carries no checking of its own; its value is that an expert in the area treats the dimension-three characteristic-two result as established and knows its history. The anonymous comment it replies to asserts the stronger statement that the separable conjecture fails in every dimension above one, citing both preprints. Sep 14, 2026
- Mondello's counterexample to the two-dimensional separable Jacobian conjecture in characteristic two is correct.
Without evidence. The comment is the same commentator's announcement made in a second venue on the same day; it carries no checking of its own. The full thread was not opened in this pass, only the recorded passage. Sep 14, 2026
- Claude Fable 5 generated the polynomial map used as the 2026 Jacobian conjecture counterexample
Without evidence. The post's evidence is entirely mathematical: it verifies and explains the map but says nothing about how it was found beyond the phrase "using the Fable AI". The comment thread beneath it contains readers asking what the prompts were and disputing the credit ordering, and no answer from anyone with first-hand knowledge. Sep 13, 2026
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Theorem 2 (Counterexample to conjecture) There exists a polynomial F : C^3 \rightarrow C^3 which has non-zero constant Jacobian, but is not invertible.
Not yet read by this claim’s Steward.
The conjecture remains open in two dimensions, and is easy to establish in one dimension.
Not yet read by this claim’s Steward.
But the fact is, when Abhyankar and Moh named "Jacobian conjecture" in the 1970-80s, they only referred to the 2-dimensional version.
Without evidence. The assertion is made flatly by an anonymous commenter, with no source offered. Elsewhere in the same thread a second anonymous commenter supplies the supporting anecdote (Abhyankar and Moh adopting the name privately after a remark of Zariski in the 1960s), and a third replies that the earliest printed use of the term, by Miyanishi in 1973, referred to the n-dimensional statement and predates Abhyankar's and Moh's publications on the planar problem. Tao's reply disputes the surrounding contention that the planar case was consensually the fundamental one, without addressing what Abhyankar and Moh themselves meant.
Contrary to all the hype, the Jacobian conjecture counterexample is not that exciting because it relies on techniques established by Vitushkin in his 1999 paper. So there really is nothing new here.
Not yet read by this claim’s Steward.
It was recently shown (using the Fable AI) that the conjecture is false in three dimensions
Not yet read by this claim’s Steward.
A mechanical Bass–Connell–Wright reduction of Alpöge's ℂ³ counterexample, yielding a cubic Keller map of ℂ¹⁹ that is 3-to-1 over a point.
Supports. Tao states the explicit polynomials, says both properties follow from a brief calculation, and then explains why the map is generically three-to-one: it is built from multiplication of a linear and a quadratic form, and a generic cubic splits into three linear factors, giving three preimages. The post is an independent derivation, not a restatement of the announcement.
There exists an affine variety that is isomorphic to [A³] by polynomial changes of variable, and a polynomial map which is locally injective, but not globally injective.
And here is a reward for Huq-Kuruvilla's work — the two dimensional case in characteristic two! That's really exciting. Maybe we'll see the two dimensional case in some other characteristics soon!
Without evidence. A second announcement by the same commenter, David Speyer, in Terence Tao's comment thread; it restates the news of the preprint and adds no verification of its own.
It was recently shown (using the Fable AI) that the conjecture is false in three dimensions (and thus in higher dimensions as well)
Without evidence. The post's evidence is entirely mathematical: it verifies and explains the map but says nothing about how it was found beyond the phrase "using the Fable AI". The comment thread beneath it contains readers asking what the prompts were and disputing the credit ordering, and no answer from anyone with first-hand knowledge.
And here is a reward for Huq-Kuruvilla's work — the two dimensional case in characteristic two! That's really exciting. Maybe we'll see the two dimensional case in some other characteristics soon!
Without evidence. The comment is the same commentator's announcement made in a second venue on the same day; it carries no checking of its own. The full thread was not opened in this pass, only the recorded passage. Read from the quoted passage alone.
The first observation about passing to characteristic 2, dimension 3, has been recorded elsewhere; see Timothy Chow https://mathoverflow.net/a/513393/297 and N8Programs https://xcancel.com/N8Programs/status/2079061392649302185 . That said, I am in favor of results being recorded in clearly written versions posted to repositories like the arXiv, so good for Irit Huq-Kuruvilla for putting in the work.
Without evidence. The comment is the same commentator's announcement made in a second venue on the same day and carries no checking of its own; its value is that an expert in the area treats the dimension-three characteristic-two result as established and knows its history. The anonymous comment it replies to asserts the stronger statement that the separable conjecture fails in every dimension above one, citing both preprints.
Contrary to all the hype, the Jacobian conjecture counterexample is not that exciting because it relies on techniques established by Vitushkin in his 1999 paper. So there really is nothing new here. The only thing different is that here it’s applied to three dimensions and one gets a polynomial map, whereas in two dimensions one only gets a rational map.
Without evidence. An anonymous comment states the parallel to Vitushkin's 1999 paper without working it out; replies in the thread accept the general idea while calling the "nothing new" framing extreme, and a later comment locates Vitushkin's example as the linear-times-linear case of the factorisation construction that Tao's post develops for linear-times-quadratic. The thread thus records agreement on the structural parallel and disagreement only about what it implies for novelty.
People concentrated on 2D because it’s the most attractive (with too many wrong proofs) and disproving it leads to disproving all dimensions. The latter is considered by Vitushkin, who clearly focused on finding the obstruction for an easy 2D counter example without caring about 3D or higher.
Without evidence. A short anonymous comment with no argument or citation behind it. Its phrasing closely resembles the Wikipedia talk-page comment of the previous day and the two may be one voice.
It was recently shown (using the Fable AI) that the conjecture is false in three dimensions (and thus in higher dimensions as well)
Supports. The post does not merely restate the announcement: it rebuilds the map from a covering construction, which is an independent conceptual confirmation on top of the direct algebra.
The mechanism does not descend to the plane through any slice so far tested.
Supports. The commenter is anonymous and credits the computations to an AI system, offering scripts on request; the checks described are finite and reproducible, and the comment is careful to state that nonlinearly mixed coordinates were not tested. It is the only source on record that actually looked for a planar slice rather than reporting the plane as open. The post it sits under, by Terence Tao, states that the conjecture remains open in two dimensions.
So finding such a polynomial looks highly unlikely to be located by brute force.
Supports. Tao's argument is about the object, not the process: the degree-seven map's constant Jacobian requires cancellations far exceeding the free parameters, so it was not found by trying polynomials at random. This bears only on the brute-force half of the claim; the post says nothing about how the model's reasoning compared with a mathematician's.
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History 12
- Sep 16, 2026ReadingSteward of “Frontier AI models produce novel mathematical r…” · supports, read whole
- Sep 16, 2026ReadingSteward of “No known construction converts the three-dimens…” · supports, read whole
- Sep 16, 2026ReadingSteward of “The separable Jacobian conjecture is false in d…” · asserts without evidence, read whole
- Sep 16, 2026ReadingSteward of “When Abhyankar and Moh introduced the term 'Jac…” · asserts without evidence, read whole
- Sep 16, 2026ReadingSteward of “Alpöge's map (a,b,c) on ℂ³ has constant Jacobia…” · supports, read whole
- Sep 15, 2026ReadingSteward of “A counterexample to the Jacobian conjecture in…” · supports, read whole
- Sep 14, 2026ReadingSteward of “Vitushkin's construction method faces an obstru…” · asserts without evidence, read whole
- Sep 14, 2026ReadingSteward of “The 2026 Jacobian conjecture counterexample clo…” · asserts without evidence, read whole