Conjecture · version 2

The two-variable Jacobian question

Statement

Every polynomial map F: C2\mathbb C^2 → C2\mathbb C^2 with constant nonzero Jacobian determinant has a polynomial inverse.

Assumptions

  • Exactly two complex variables.

Scope

The source leaves this dimension open; the three-variable witness cannot be specialized to refute it.

Evidence

Connections

In this problem · publication v8

Jacobian conjecture →

Different statement · related variant · Open

Related statements

The three-variable witness settles the universal formulation, while the two-variable restriction remains a different question.

A collision in ℂ³ supplies no counterexample in ℂ².

Details & sources
A constant determinant with three inputs sharing an output →

Proved · version 3

Set s=xys=xy and u=1+su=1+s. The map F(x,y,z)=(u3z+y2u(4+3s)y+3xu2z+3xy2(4+3s)2x−3x2y−x3z)F(x,y,z)=\begin{pmatrix}u^3z+y^2u(4+3s)\\ y+3xu^2z+3xy^2(4+3s)\\2x-3x^2y-x^3z\end{pmatrix} has det⁡JF=−2\det JF=-2. The distinct inputs (0,0,−1/4), (1,−3/2,13/2) and (−1,3/2,13/2) all map to (−1/4,0,0).

  • Use the displayed map over a characteristic-zero field.

Scope: A concrete failure of injectivity and hence of a polynomial inverse. The coordinate degrees are 7, 6 and 4; a cubic fiber relation does not make this a cubic coordinate map.

The two-variable Jacobian question →

Open · version 2

Every polynomial map F: C2\mathbb C^2 → C2\mathbb C^2 with constant nonzero Jacobian determinant has a polynomial inverse.

  • Exactly two complex variables.

Scope: The source leaves this dimension open; the three-variable witness cannot be specialized to refute it.

Relationship not independently reviewed.

Connection in Jacobian conjecture →

Relationship not independently reviewed. This concerns its use in this problem.

Sources

Counterexamples to the Jacobian conjecture in dimensions greater than two →

Shuhong Gao · Preprint · Publication date Jul 31, 2026

Public manuscript or exposition; publication does not imply independent OpenMath review.

Revision & attribution

Source revision: 2026-07-31. Observed Oct 13, 2026.

No AI contribution is asserted by this source record.

Source updated Jul 31, 2026.

A Counterexample to the Jacobian Conjecture →

ULAM research manuscript (no author named) · Preprint · Publication date Jul 20, 2026

Public manuscript or exposition; publication does not imply independent OpenMath review.

Revision & attribution

Source revision: 2026-07-20. Observed Oct 13, 2026.

The manuscript cites Levent Alpöge’s announcement, credits Akhil Mathew for asking the question and Fable for the work leading to the example. No named author is printed on this verification manuscript; these discovery credits are not its bibliographic authorship.

Source updated Jul 20, 2026.

Alpöge counterexample in Lean →

alerad/alpoge-lean project · Project documentation · Publication date Jul 23, 2026

Public formal source; build and independent mathematical review are separate checks.

Revision & attribution

Source revision: b8eec94711a9b73151929b78cbd7cb999a008590. Observed Oct 13, 2026.

The project reports an AI-assisted formalization and computer-algebra workflow; this is distinct from the original discovery.

Source updated Jul 23, 2026.

History

Statement versions

Statement versions and problem publication versions are separate. A new publication can update context or sources while retaining the same statement.

Assessment history · 1

Assessments retained in these publication records. Earlier statement versions retain their own source histories.

Record details
Claim ID
claim-jacobian-dimension-two
Statement version
2
SHA-256
68010ca5e2dcb4581b3c3fc43162e4da4eac23e453f7e3c1a72661fd7a7eb7cf

Publication records