New Approaches to Parsing Conjunctions Using Prolog

Conjunctions are particularly difficult to parse in traditional, phra.se-based gramniars. This paper shows how a different representation, not b.xsed on tree structures, markedly improves the parsing problem for conjunctions. It modifies the union of phra.se marker model proposed by GoodalI [19811, where conjllnction is considered as ti le linearization of a three-dimensional union of a non-tree I),'med phrase marker representation. A PItOLOG grantm~tr for conjunctions using this new approach is given. It is far simpler and more transparent than a recent phr~e-b~qed extraposition parser conjunctions by Dahl and McCord [1984]. Unlike the Dahl and McCor, I or ATN SYSCONJ appr~ach, no special trail machinery i.~ needed for conjunction, beyond that required for analyzing simple sentences. While oi contparable ¢tficiency, the new ~tpproach unifies under a single analysis a host of related constructions: respectively sentences, right node raising, or gapping. Another ,'ulvanrage is that it is also completely reversible (without cuts), and therefore can be used to generate sentences. John and Mary went to tile pictures Ylimplc consti tuent coordhmtion Tile fox and tile hound lived in tile fox hole and kennel respectively CotJstit,wnt coordination "vith r.he 'resp~ctively' reading John and I like to program in Prolog and Hope Simple consti tmvR co~rdinatiou but c,~, have a collective or n.sp,~'tively reading John likes but I hate bananas ~)tl-c,mstitf~ent coordin,~tion Bill designs cars and Jack aeroplanes Gapping with 'resp,~ctively' reading The fox. the honnd and the horse all went to market Multiple c,mjunets *John sang loudly and a carol Violatiofl of coordination o f likes *Wire (lid Peter see and tile car? V/o/atio/i of roisrdJ)l=lte str¢/¢'trlz'e constr.~int *1 will catch Peter and John might the car Gapping, hut componcztt ~cnlenccs c.ntain unlike auxiliary verbs ?Tire president left before noon and at 2. Gorbachev