| Also, objects that are not isomorphic in one category might become isomorphic when a functor is applied. |
| Furthermore, we prove some theorems about the inversion of functor structures. |
| In this, as in some other articles the operation of modelling is represented as a functor in the categorical language. |
| A constituent is defined as a compound term of arity 1 with the constituent category as principal functor. |
| In fact, essentially every invariant studied by topologists can be made into a representable or corepresentable functor. |
| Happen is represented as having the valency of an absolutive functor and a locative. |
