Macaulay2 / Macaulay2/M2

Hom between modules over different rings

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Core
Dominant language
Macaulay2
Stars
435
Forks
297
Avg merge
4d 20h
Merged PRs (30d)
11

Description

Currently the implementation of Hom(M, N) convert both modules to the same ring in an ambiguous way, causing incorrect results:
```m2
i1 : K = ZZ/11;

i2 : S = K[x,y];

i4 : Hom(S^1, K^1)

1
o4 = S

o4 : S-module, free

i5 : Hom(S^1, coker vars S)

o5 = cokernel | y x |

1
o5 : S-module, quotient of S
```

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First steps

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  3. Fork the repository and make your change on a branch.
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Research direction

No source file, test, or entry point is named. Start by reproducing the provided Macaulay2 session comparing Hom(S^1, K^1) and Hom(S^1, coker vars S), then trace how modules over different rings are converted; done means the conversion is unambiguous and both results are mathematically correct.

Written by the indexing model from the issue text.

Assessment

Domain
tooling
Issue type
Bug
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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