EMP: An expert system for mathematical programming. The paper describes a software system that supports model building and numerical solution of various mathematical programming problems, e.g. of nonlinear programming, data fitting, min-max programming, multicriteria optimization, nonsmooth optimization, quadratic programming, or linear programming, subject to linear or nonlinear constraints. All actions of the system are controlled by menues which inform the user how to generate, solve, edit, delete or list a problem, for example. Nonlinear problem functions must be defined by sequences of FORTRAN statements assigning a numerical value to a user-provided name. The system writes a complete FORTRAN source program, which is linked and executed automatically. All problem data and numerical results are stored in a data base and are easily retrieved for further processing. For each nonlinear problem, at least two different mathematical algorithms are available. The system is capable to learn, i.e. to improve its own knowledge on the success of the algorithms, and to perform a rule-based error analysis in case of nonsuccessful termination.