HOMOMORPHISMS AND PROMOTABILITY
Grant Malcolm · University of Groningen research database (University of Groningen / Centre for Information Technology) · 1989
The construction of structure-preserving maps, or “homomorphisms,” is described for an arbitrary data type: examples of these functions are given for list- and tree-like structures and types defined by mutual induction. From the definition of a data type it is also possible to infer a “promotion” theorem for proving equalities of homomorphisms.