6 Ring Relations 6.1 Ring Relations: Categories and Representations 6.1-1 IsHomalgRingRelations IsHomalgRingRelations( rel )  Category Returns: true or false The GAP category of homalg ring relations. 6.1-2 IsHomalgRingRelationsAsGeneratorsOfLeftIdeal IsHomalgRingRelationsAsGeneratorsOfLeftIdeal( rel )  Category Returns: true or false The GAP category of homalg ring relations as generators of a left ideal. (It is a subcategory of the GAP category IsHomalgRingRelations.) 6.1-3 IsHomalgRingRelationsAsGeneratorsOfRightIdeal IsHomalgRingRelationsAsGeneratorsOfRightIdeal( rel )  Category Returns: true or false The GAP category of homalg ring relations as generators of a right ideal. (It is a subcategory of the GAP category IsHomalgRingRelations.) 6.1-4 IsRingRelationsRep IsRingRelationsRep( rel )  Representation Returns: true or false The GAP representation of a finite set of relations of a homalg ring. (It is a representation of the GAP category IsHomalgRingRelations (6.1-1)) 6.2 Ring Relations: Constructors 6.3 Ring Relations: Properties 6.3-1 CanBeUsedToDecideZero CanBeUsedToDecideZero( rel )  property Returns: true or false Check if the homalg set of relations rel can be used for normal form reductions. (no method installed) 6.3-2 IsInjectivePresentation IsInjectivePresentation( rel )  property Returns: true or false Check if the homalg set of relations rel has zero syzygies. 6.4 Ring Relations: Attributes 6.5 Ring Relations: Operations and Functions