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elements_of_irrelevant_ideal :=
[ "x", "y" ];
IsSupportedInOrigin := function( module_presentation )
local number_of_generators, list_of_generators, list_of_kernel_embeddings, ideal_embedding,
ideal_matrix, Fn1, F1, S, Sy, elem, matrix, entry;
number_of_generators := NrColumns( UnderlyingMatrix( module_presentation ) );
if number_of_generators = 0 then
return true;
fi;
list_of_generators := List( [ 1 .. number_of_generators ], i -> StandardGeneratorMorphism( module_presentation, i ) );
list_of_kernel_embeddings := List( list_of_generators, KernelEmbedding );
ideal_embedding :=
PreCompose( ProjectionInFactorOfFiberProduct( list_of_kernel_embeddings, 1 ), list_of_kernel_embeddings[1] );
SetIsMonomorphism( ideal_embedding, true );
S := UnderlyingHomalgRing( module_presentation );
Sy := S * "RabinowitschTrickVariable";
ideal_matrix := UnderlyingMatrix( ideal_embedding ) * Sy;
Fn1 := FreeLeftPresentation( NrRows( ideal_matrix ) + 1, Sy );
F1 := FreeLeftPresentation( 1, Sy );
for elem in elements_of_irrelevant_ideal do
entry := HomalgMatrix( [ [ elem ] ], 1, 1, S );
entry := entry * Sy;
entry := entry * HomalgMatrix( [ [ "RabinowitschTrickVariable" ] ], 1, 1, Sy ) - HomalgMatrix( [ [ "1" ] ], 1, 1, Sy );
matrix := UnionOfRows( ideal_matrix, entry );
if not IsEpimorphism( PresentationMorphism( Fn1, matrix, F1 ) ) then
return false;
fi;
od;
return true;
end;;
SwitchGeneralizedMorphismStandard( "span" );
[ Dauer der Verarbeitung: 0.4 Sekunden
(vorverarbeitet)
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