AbstractThe purpose of knowledge representation for an expert system is to specify functions to be performed by the system. In this paper, a knowledge representation scheme which mutually combines procedures, functions, production rules and Horn clauses is outlined. Its knowledge representation model is an imaginary organisation for performing functions of a target system, where a number of members try to solve given problems systematically. Knowledge is distributed to each of the members with considerable modularity. Functional specification of expert systems would be performed with less difficulty.