ATN

ATN augmented transition network.
atom 1. in propositional or predicate calculus, a predicate symbol with the appropriate number of arguments.

Woods introduced the augmented transition network (ATN) to represent natural language input.[4] Instead of phrase structure rules ATNs used an equivalent set of finite state automata that were called recursively.

See also: Knowledge, Natural language processing, Natural language understanding, Artificial intelligence, NLP