Macaulay2 / Macaulay2/M2

isWellDefined isn't working with Weyl algebras

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Core
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Macaulay2
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Description

Consider the following:

i1 : needsPackage "Dmodules";

i2 : W = makeWeylAlgebra(QQ[y,z]);

i3 : W' = makeWeylAlgebra(QQ[x,y,z]);

i4 : phi = map(W', W, {y, z, y*dx, z*dx});

o4 : RingMap W' <--- W

i5 : isWellDefined phi

o5 = true

i6 : use W;

i7 : phi(dy) * phi(y) - phi(y)*phi(dy)

o7 = 0

o7 : W'

Evidently, M2 thinks phi is well defined. However, according to o7, it is not.

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  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 example after loading Dmodules, using makeWeylAlgebra and isWellDefined on the shown map. Start by tracing how isWellDefined validates maps between Weyl algebras; done means the displayed invalid map is rejected or correctly identified as not well defined.

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
35/100

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