- Extensions to HTML with categories, relations and inferences
- KIF is a descriptive logic based on first-order predicate calculus (FOL) containing objects, functions and relations.
- A variant of KIF with reasoning facilities
- A frame-based KR language with FOL semantics.
- A language for communication between software agents.
- A lisp like language for exchange of knowledge
- A logical KR language with support for (ontological) definitions and reasoning.