The Preliminary Design Ofan Object - Oriented

The design of an object-oriented framework for combinatorial enumeration is described. Combinatorial enumeration requires a subtle interplay between the search mechanism, the ordering of the space of combinatorial objects, and the symmetries used to prune equivalent cases from the search. EEciency requires that pruning be used as much as possible, while correctness requires the pruning not be used more than is provably correct. The framework is the product of an evolutionary process of modelling and of attempts at precise (but not formal) mathematical speciication of the framework. Our approach to specifying the framework, and documenting how it should be instantiated for a particular combinatorial enumeration, is to list the proof obligations that must be satissed by the user-supplied components. This work reports our preliminary object-oriented design of the framework, with only brief mention of the use of proof obligations.