When a reasoning system adopts the closed world assumption, it assumes that all facts (within its domain) are present in its knowledge base. That is if a fact is not in the knowledge base, it is deemed to be false. The logic programming language Prolog adopts a closed world assumption. The opposite is an open world assumption.
Used in Chap. 2: page 16; Chap. 17: pages 252, 253
Used in glossary entries: knowledge base, logic programming, open world assumption, Prolog