  In order to study AS-regular algebras of dimension 5, we consider dimension 5
graded iterated Ore extensions generated in degree one. We classify the
possible degrees of relations and structure of the free resolution for
extensions with 3 and 4 generators. We show that every known type of algebra of
dimension 5 can be realized by an Ore extension and we consider which of these
types cannot be realized by an enveloping algebra.
