Injective Modules over Down-Up Algebras

The purpose of this paper is to study finiteness conditions on injective hulls of simple modules over Noetherian Down-Up algebras. We will show that the Noetherian Down-Up algebras A(\alpha,\beta,\gamma) which are fully bounded are precisely those which are module-finite over a central subalgebra. We show that injective hulls of simple A(\alpha,\beta,\gamma)-modules are locally Artinian provided the roots of X^2-\alpha X-\beta are distinct roots of unity or both equal to one.