ABSTRACT

The most highly developed metaphor of problem solving is that of search through a finitely branching network of alternatives. Human cognitive abilities doubtlessly encompass other important forms, but this paradigm clearly covers a wide variety of important cases. Problem-specification language, psl is a formally defined language that can be used to give precise specifications for a class of problems. A psl permits variable names to be typed, that is, the range of permissible values to which a variable may be bound is specifiable. This permits classification of variables into such types as human personal names, real numbers, positive integers, signed integers, and sets of each of these types. In many types of problems, diagrams are used in presenting the problem and the solution attempts. Often, the scale and other geometric features of the problem are irrelevant to its essence, although particular values must be selected for presentation.