Richard Waldinger. Whatever Happened to Deductive Question Answering?, in 14th International Conference on Logic for Programming, Artificial Intelligence, and Reasoning, Springer-Verlag, 2007.
Deductive question answering, the extraction of answers to questions from machine-discovered proofs, is the poor cousin of program synthesis. It involves much of the same technology–theorem proving and answer extraction–but the bar is lower. Instead of constructing a general program to meet a given specification for any input–the program synthesis problem–we need only construct answers for specific inputs; question answering is a special case of program synthesis. Since the input is known, there is less emphasis on case analysis (to construct conditional programs) and mathematical induction (to construct looping constructs), those bugbears of theorem proving that are central to general program synthesis. Program synthesis as a byproduct of automatic theorem proving has been a largely dormant field in recent years, while those seeking to apply theorem proving have been scurrying to find smaller problems, including question answering.
Keywords: Artificial Intelligence, Artificial Intelligence Center, AIC, deductive question answering, program synthesis, theorem proving, Semantic Web, procedural attachment