Repair flattenings of graded modules #3217
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| @@ -28,7 +28,7 @@ function presentation(SQ::SubquoModule) | |||
| end | |||
| else | |||
| if is_graded(SQ) | |||
| s, _ = kernel(graded_map(ambient_free_module(SQ), gens(SQ.sum))) | |||
| s, _ = kernel(graded_map(ambient_free_module(SQ), filter(!iszero, gens(SQ.sum)))) | |||
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@jankoboehm : There is an issue when calling graded_map with any zero in the second argument. The error could be fixed here by adding the filter, but I am not 100% sure this is legitimate. Either way, the rest of the code for presentation should eventually be checked as to whether it suffers from similar issues. But I found it too hard to read to actually understand what's going on and simply adding filter to the other calls to graded_map made things worse. So I only did this one change for the moment.
| @@ -1000,7 +1000,8 @@ function is_zero(m::SubquoModuleElem) | |||
| return (ambient_representative(m) in parent(m).quo) | |||
| end | |||
|
|
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| function iszero(m::SubquoModuleElem{<:MPolyRingElem}) | |||
| # Method only for the cases which can be handled by singular | |||
| function iszero(m::SubquoModuleElem{<:MPolyRingElem{T}}) where {T<:Union{<:FieldElem, ZZRingElem}} | |||
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@jankoboehm : This function is not generic, but works only for rings with a singular backend. When writing up your different module layers, this should be corrected, eventually.
Codecov Report
Additional details and impacted files@@ Coverage Diff @@
## master #3217 +/- ##
==========================================
- Coverage 81.62% 81.58% -0.04%
==========================================
Files 545 545
Lines 72751 72812 +61
==========================================
+ Hits 59381 59406 +25
- Misses 13370 13406 +36
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* let `right_cosets` return a G-set - add `GSetByRightTransversal` - change `right_cosets` to return a `GSetByRightTransversal` object - change `show` methods for `GSetByElements` and `GroupCoset` * address comments * adjust `show` values
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Some improvements to handle certain derived pushforwards requested by externals. See the added tests for details.