Abstract
We continue the classification, begun in [11], [14] and [12], of quadratic Artin-Schelter regular algebras of global dimension 4 which map onto a twisted homogeneous coordinate ring of a quadric hypersurfcice in P3. In this paper, we consider those cases where the quadric has rank 3. We also give sufficient conditions for the point scheme of any quadratic regular algebra of global dimension 4 to be the graph of an automorphism.
*The second author was supported in part by NSF grant DMS-9622765.
*The second author was supported in part by NSF grant DMS-9622765.
Notes
*The second author was supported in part by NSF grant DMS-9622765.