Macaulay2 / Macaulay2/M2

Problem with WeylClosure function in D-modules

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#4,027 3 comments 0 reactions 0 assignees View on GitHub

@michaelPerlman is already working on this.

Since Jul 7, 2026.

  • #4467 by @michaelPerlman — open
WeylAlgebras
Dominant language
Macaulay2
Stars
435
Forks
297
Avg merge
4d 20h
Merged PRs (30d)
11

Description

`loadPackage "BernsteinSato"`
`makeWA(QQ[x])`
`I = ideal(x^2*dx^2 -2*x*dx + 1)`
`WeylClosure I`

outputs the error message
`stdio:15:11:(3): error: internal error: incorrect b-function`

instead of computing the Weyl closure of the ideal as intended.

I had a brief correspondence with Anton Leykin in which he suggests the problem might be caused by the code for Drestriction assiming the b-function needs to have rational roots.

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Reproduce the failure with the BernsteinSato, makeWA, ideal, and WeylClosure commands shown in the issue, then read the Drestriction path and the linked pull request #4467. Done means the example computes the Weyl closure without the “incorrect b-function” internal error, with coverage for this case.

Written by the indexing model from the issue text.

Assessment

Domain
tooling
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
25/100

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