Macaulay2 / Macaulay2/M2

minimalBetti fails for zero modules

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Macaulay2
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Description

With Complexes:

i1 : S = ZZ/2[x]; minimalBetti coker map(S^0, S^0, 0)
stdio:1:25:(3): error: key not found in hash table:
        ResolutionObject (of class Symbol)

But at least this failed with OldChainComplexes, too:

i1 : S = ZZ/2[x]; minimalBetti coker map(S^0, S^0, 0)
Internal error: (-1,1) out of range

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Research direction

Reproduce the minimalBetti commands shown for Complexes and OldChainComplexes, focusing on the zero-module case. Trace the implementation reached by minimalBetti and compare both failures; done means the zero-module input is handled without a hash-table or range error.

Written by the indexing model from the issue text.

Assessment

Domain
backend
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
48/100

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