What is the fine-grained topic of the following text: With the aid of a natural bilinear program, we establish various properties of this extended complementarity problem; these include the convexity of the bilinear objective function under a monotonicity assumption, the polyhedrality of the solution set of a monotone XLCP, and an error bound result for a nondegenerate XLCP. Only return the topic.
Properties of the extended complementarity problem in a natural bilinear program