DeclareAttribute( "AlmostSplitSequence", IsPathAlgebraMatModule );
DeclareOperation( "AlmostSplitSequenceInPerpT", [ IsPathAlgebraMatModule, IsPathAlgebraMatModule ] );
DeclareOperation( "PredecessorsOfModule", [ IsPathAlgebraMatModule, IS_INT ]) ;
DeclareAttribute( "IrreducibleMorphismsEndingIn", IsPathAlgebraMatModule );
DeclareAttribute( "IrreducibleMorphismsStartingIn", IsPathAlgebraMatModule );