Building a knowledge base: an example

The main goal of this paper is to illustrate applications of some recent de velopments in the theory of logic programming to knowledge representation a nd reasoning in common sense domains. We are especially interested in bette r understanding the process of development of such representations together with their specifications. We build on the previous work of Gelfond and Pr zymusinska in which the authors suggest that, at least in some cases, a for mal specification of the domain can be obtained from specifications of its parts by applying certain operators on specifications called specification constructors and that a better understanding of these operators can substan tially facilitate the programming process by providing the programmer with a useful heuristic guidance. We discuss some of these specification constru ctors and their realization theorems which allow us to transform specificat ions built by applying these constructors to declarative logic programs. Pr oofs of two such theorems, previously announced in a paper by Gelfond and G abaldon, appear here for the first time. The method of specifying knowledge representation problems via specification constructors and of using these specifications for the development of their logic programming representatio ns is illustrated by design of a simple, but fairly powerful program repres enting simple hierarchical domains.