Expressing quantifier scope in French generation

Expressing quantifier scope in French generation Pierre-Joseph GAILLY * Computer Science Department, University of Liege, B4000 Li~ge~ Belgium Abstract In this paper we propose a new method to express quantifica- tion and especially quantifier scope in French generation. Our approach is based on two points: the identification of the sen- tence components between which quantifier scope can indeed be expressed and a mechanism to reinforce the expression of quantifier scope. This approach is being integrated in a writ- ten French generator , called Hermes, which will become the generator of a portable natural language interface. 1 Introduction Natural language interfaces are being applied to various ap- plications; most of them, especially data base and expert sys- tem interfaces, require the production of precise texts. One of the key problems of precision is the correct expression of quantifier type and scope. Our research has led us to identify a new practical method to express quantification in a precise and natural way and to im- plement our approach in the portable written French generator called Hermbs (/Gailly 87a/and/Gailly 875/) to be integrated in a portable natural language interface (/Binot, Gailly & Rib- bens 86/). The generator's goal is to produce French sentences from a message (a representation of their meaning) expressed in Formula, a representation language based on an extension of first order predicate calculus. The main point of our approach is the identification of the importance of properly choosing- the determiners in noun phrases in conjunction with the selection of the surface structure of the sentences produced. However, we must stress the fact that we are not trying to provide a theoret- ical and comprehensive study of how quantification is expressed in natural language (such as in the work of/Cooper 83/). In the rest of this paper we will first discuss the difference between the problems raised by quantification in parsing and generation, then discuss the present approaches to the problem and finally present our own approach. 2 The difference between understanding and generating quantifier scope In understanding, the problem is, starting from the input sentence, to identify the quantifier scope intended by the user. In presence of an ambiguous sentence, the system will use all available information (i.e. syntactic structure, word choice and order, semantic and pragmatic knowledge, context and dialog history) to find the most plausible quantifier order. Consider: Ex. 1 Un homme meurt tou~ los soirs. (A man dies all evenings)) Ex. 2 Chaquc s:oir un homme meurt. (Every evening a man dies.) Although the first example is poorly expressed, a clever un- derstanding system should comprehend both sentences in the same way, as human beings do, because the interpretation "The same man dies every evening." is nonsensical. If the verb "mcurt" ("dies") is replaced by "mange chcz Paul" ("eats at Paul's place'), the two sentences have different meanings and the system should understand them in different ways. *Research sponsored by the Institut pour l'Encouragement de la Recherche Scientifique dens PIndustrie et l'Agricultnre (LR.S.I.A.). 1Though we have trie&.to …

Content truncated to 500 words