Ichiki@sri-unix.UUCP (09/13/83)
. This type of information, however, does not lend itself to an immediate representation on the object level. Since there are no known proof procedures for higher order logics we have to find makeshift solutions for a suitable text representation with appropriate interpretation procedures. One way is to use the subset of First Order Predicate Calculus as defined by Prolog as a representation language, and a General Purpose Planner (implemented in Prolog) as an interpreter. Answering a question over a textual data base can then be reduced to proving the answer in a model of the world as described in the text, i.e. to planning a sequence of actions leading from the state of affairs given in the text to the state of affairs given in the question. The meta-level information contained in the text is used as control information during the proof, i.e. during the execution of the simulation in the model. Moreover, the format of the data as defined by the planner makes explicit some kinds of information particularly often addressed in questions. The simulation of an experiment in the Blocks World, using the kind of meta-level information important in real scientific experiments, can be used to generate data which, when generalised, could be used directly as DB for question answering about the experiment. Simultaneously, it serves as a pattern for the representation of possible texts describing the experiment. The question of how to translate NL questions and NL texts, into this kind of format, however, has yet to be solved.