a1 Mathematics Department, University of Missouri, Columbia, MO 65211, USA e-mail: firstname.lastname@example.org
For the Kronecker algebra, Zwara found in  an example of a module whose orbit closure is neither unibranch nor Cohen-Macaulay. In this paper, we explain how to extend this example to all representation-infinite algebras with a preprojective component.
(Received August 05 2011)
(Revised October 18 2011)
(Accepted October 19 2011)
(Online publication March 30 2012)
2000 Mathematics Subject Classification