ABSTRACT
A homomorphism is an algebraic transformation that plays a large role in blockmodeling. However, it is unclear what homomorphisms are in terms of transformations of the data. What is the relation between the homomorphic image of a semigroup and the matrices that generated the semigroup? Homomorphisms are algebraic simplifications, but do they imply a corresponding simplification of the data? This is the basic issue of this chapter.
