A General Computational Treatment Of The Comparative

A General Computational Treatment Of The Comparative Carol Friedman" Courant Institute of Mathematical Sciences New York University 715 Broadway, Room 709 New York, NY 10005 Abstract We present a general treatment of the com- parative that is based on more basic linguistic elements so that the underlying system can be effectively utilized: in the syntactic analy- sis phase, the comparative is treated the same as similar structures; in the syntactic regular- ization phase, the comparative is transformed into a standard form so that subsequent pro- ceasing is basically unaffected by it. The scope of quantifiers under the comparative is also in- tegrated into the system in a general way. 1 Introduction Recently there has been interest in the devel- opment of a general computational treatment of the comparative. Last year at the Annual ACL Meeting, two papers were presented on the comparative by Ballard [1] and Rayner and Banks [14]. Previous to that a compre- hensive treatment of the comparative was in- corporated into the syntactic analyzer of the Linguistic String Project [15]; in addition the DIALOGIC grammar utilized by TEAM [9] also contains some coverage of the compara- tive. An interest in the comparative is not sur- prising because it occurs regularly in lan- *This work was supported by the Defense Ad- vanced Re.arch Projects Agency under Contract N00014-8.5-K-0163 from the Office of Naval Research. The author's current addr¢~ is: Center for Medical Infornmti~, Columhia~Pre~byterian Medical Center, Columbia University, 161 Fort Waahington Avenue, Room 1310, New York NY 10032. guage, and yet is a very difficult structure to process by computer. Because it can occur in a variety of forms pervasively throughout the grammar, its incorporation into a NL system is a major undertaking which can easily ren- der the system unwieldy. We will describe an approach to the computational treatment of the comparative, which provides more general coverage of the comparative than that of other NLP Systems while not obscuring the underly- ing system. This is accomplished by associat- ing the comparative with simpler, more basic linguistic entities so that it could be processed by the system with only minor modifications. The implementation of the comparative de- scribed in this paper was done for the Pro- re,8 Question Answering System [8] 1 (referred to hereafter as Proteus QAS), and should be adaptable for other systems which have sim- ilar modules. A more detailed discussion of this work is given in [7]. 1.1 The Problem The comparative is a difficult structure to pro- cess for both syntactic and semantic reasons. Syntactically the comparative is extraordinar- ily diverse. The following sentences illustrate a range of different types of comparative struc- tures, some of which resemble other English structures, as noted by Sager [15]. In the ex- amples below, sentences with the comparative that resemble other forms are followed by a 1 The treatment of the comp~'ative in the syntac- tic analysis component was adapted from a previous implementation done by this 8uthor for the Linguistic String Project [15]. 161 sentence …

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