In this chapter we apply the hypersubstitution operation studied in the previous chapter to the Computer Science concepts from Chapters 7 and 8. Our first application is a generalization of the unification problem, which plays an important role in term rewriting systems and logical programming. It is natural to consider the hyperunification problem, which arises when we use hypersubstitutions instead of ordinary substitutions. The second application in this chapter is the generalization of tree-recognizers to hyper-treerecognizers. Finally, we consider tree transformations and tree transducers generated by hypersubstitutions.