oscar-system / Singular.jl

Julia package for the Singular library
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Inconsistent output of `prune_with_map_projection` #796

Closed RafaelDavidMohr closed 1 month ago

RafaelDavidMohr commented 3 months ago

The output of prune_with_map_projection is not consistent between the zero module and other modules. Consider:

julia> R, (x, y) = polynomial_ring(QQ, ["x", "y"]);

julia> F = FreeModule(R, 1);

julia> v = F([zero(R)]);

julia> M = Singular.Module(R, v);

julia> prune_with_map_projection(M)
(Singular Module over Singular polynomial ring (QQ),(x,y),(dp(2),C), with Generators:
0, [0], Int32[0])

The last entry of this output should tell me which generators of the ambient free module of M were kept around as part of a minimal generating system of F/M. So in this case it should be Int32[1] instead.

hannes14 commented 3 months ago

fixed with https://github.com/Singular/Singular/commit/5704a442d5557973dbede7f6f4f317bf9402aeff