Toh
Department of Mathematics, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260 (mattohkc@math.nus.edu.sg).

Todd
School of Operations Research and Industrial Engineering, Cornell University, Ithaca, New York 14853, USA (miketodd@cs.cornell.edu). Research supported in part by NSF through grant DMS-9505155 and ONR through grant N00014-96-1-0050.

Tütüncü
Department of Mathematical Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA (reha+@andrew.cmu.edu).