Representing knowledge and reasoning with it are important components of an intelligent system, and are two important facets of Artificial Intelligence. Another important expectation from intelligent systems is their ability to accept high level requests – as opposed to detailed step-by-step instructions, and their knowledge and reasoning ability are used to figure out the detailed steps that need to be taken. To have this ability intelligent systems must have a declarative interface whose input language must be based on logic.

Thus the author considers the all-round development of a suitable declarative knowledge representation language to be a fundamental component of knowledge based intelligence, perhaps similar to the role of the language of calculus to mathematics, and physics. Taking the calculus analogy further, it is important that a large support structure is developed around the language, similar to the integration and derivation formulas and the various theorems around calculus.

Although several languages have been proposed for knowledge representation, the language of AnsProlog* – logic programming with the answer set semantics, stands out in terms of the size and variety of the support structure developed around it. The support structure includes both implementations and use of the implementations in developing applications, and theoretical results for both analyzing and step-by-step building of theories (or programs) in this language. The support structure and the desirable properties of the language are also a testimony to the appropriateness of the language for knowledge representation, reasoning, and declarative problem solving.