CycL

Cycorp

The representation language used by the CYC knowledge base. CycL is a language with both frame-based inference and a constraint system allowing arbitrary first-order logic. It is based on first-order predicate calculus, with extensions to handle equality, default reasoning, skolemization, and some second-order features. See MELD[3].

Building Large Knowledge-Based Systems, Douglas B. Lenat & R. V. Guha, Addison-Wesley, 1989.