Revision 7aa82b67303c021ab907fa46a6ac697588c19141 authored by Mohamed Barakat on 06 July 2015, 10:48:56 UTC, committed by Mohamed Barakat on 06 July 2015, 10:51:39 UTC
1 parent 0151a87
TorExt_via_Hom(P,P).g
Read( "homalg.g" );
W := ByASmallerPresentation( M );
## compute a free resolution of W
P := Resolution( W );
## instead of applying the inner functor G := Hom(-,R) to the resolution P
## and then tensoring with with P, one can directly compute Hom(P,P);
FGP := Hom( P, P );
## the bicomplex associated to FGP
BC := HomalgBicomplex( FGP );
p_degrees := ObjectDegreesOfBicomplex( BC )[1];
## the second spectral sequence together with
## the collapsed first spectral sequence
II_E := SecondSpectralSequenceWithFiltration( BC, p_degrees );
filt := FiltrationBySpectralSequence( II_E );
ByASmallerPresentation( filt );
m := IsomorphismOfFiltration( filt );
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