GENERAL INFORMATION
The Mixed Complementarity Problem, or MCP is a fundamental problem in optimization that encompasses many of the continuous optimization problems as special cases. It is useful for expressing systems of nonlinear inequalities and equations; the complementarity also allows boundary conditions be to specified in a succinct manner. Problems of this type occur in many branches of the sciences, including mathematics, engineering, economics, operations research, and computer science.
Some papers on complementarity, along with some surveys with lots of references are available.
Some futher details on algorithms and software are available.
A report on the recent meeting: International Conference on Complementarity Problems ICCP99.