Some optimization reformulations of the extended linear complementarity problem

We consider the extended linear complementarity problem (XLCP) introduced b y Mangasarian and Pang [22], of which the horizontal and vertical linear co mplementarity problems are two special cases. We give some new sufficient c onditions for every stationary point of the natural bilinear program associ ated with XLCP to be a solution of XLCP. We further propose some unconstrai ned and bound constrained reformulations for XLCP, and study the properties of their stationary points under assumptions similar to those for the bili near program.