Preliminary mathematical note · 20 July 2026

Explicit Weyl and Poisson lifts of Alpöge's Jacobian counterexample

Two classical lifts of the announced dimension-three Keller map: an injective, non-surjective endomorphism of the third Weyl algebra and an injective, non-surjective endomorphism of the canonical polynomial Poisson algebra.

Exact claim. For every field K of characteristic zero and every n ≥ 3:

An(K) has an explicit injective, non-surjective endomorphism;
Pn(K) has an explicit injective, non-surjective Poisson endomorphism.

Consequently, the generalized Dixmier and Poisson conjectures fail in every rank n ≥ 3. The rank-one and rank-two cases are untouched.

2 explicit algebraic lifts
n ≥ 3 all characteristic-zero ranks covered
2 exact verifier implementations

Status. This is a rapidly prepared preliminary note about a newly announced counterexample. The required polynomial identities are checked in exact arithmetic by two independent implementations, but the note has not undergone ordinary peer review.

Paper and verification artifacts

The SymPy implementation derives the inverse Jacobian, verifies the Weyl and Poisson relations, and generates the displayed operators. A second implementation checks the same polynomial identities using only Python's standard library.

Run locally

python -m pip install -r requirements.txt
python run_checks.py

The successful final line is:

ALL EXACT VERIFICATION CHECKS PASSED

Release archive checksum: weyl-poisson-lifts-release.zip.sha256

Public constructions and provenance

The note builds on Alpöge's announced three-dimensional map and records the classical induced Weyl and Poisson endomorphisms. Same-day independent Weyl-algebra write-ups are cited explicitly.

ContributorPublic objectScope
Alpöge / Fable 5Original Keller counterexampleDimension 3
T. RanjosIndependent exact Weyl-algebra lift and verifierA3
Omniscience ProjectIndependent formal Weyl-algebra noteA3
Present noteCombined explicit Weyl and Poisson treatment with two exact verifiersAll n ≥ 3

Contribution and AI disclosure

The counterexample map is due to Levent Alpöge, who credits Claude Fable 5 as a collaborator in its discovery. Harris Chan used Claude Fable 5, GPT-5.6 Sol, and Gemini 3.1 Pro as computational and editorial aids during the derivation, verification, and revision of this note. Their contributions included symbolic derivation and code generation, proof and presentation review, and preparation of the reproducibility package. Harris Chan reviewed the mathematical claims, executed the exact-arithmetic checks, selected and edited the final content, and takes responsibility for the work.

Citation

Please cite the PDF and include the access date while the note remains preliminary.

BibTeX
@misc{chan2026weylpoisson,
  author = {Harris Chan},
  title  = {Explicit Weyl and Poisson Lifts of
            Alpöge's Jacobian Counterexample},
  year   = {2026},
  month  = jul,
  note   = {Preliminary note},
  url    = {https://harrischan.com/docs/weyl-poisson-lifts/}
}

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