Trace & Unification Grammar

TRACE & UNIFICATION GRAMMAR liana Ulrich Block and Stefanie Schachtl Siemens AG, Corporate Research, ZFE ST SN 74 Otto Ilalm-Ring 6 D-8000 Mih*chen 83 Germany block@ztiv~x.zfe.siemens.de Abstract This paper presents Trace & Unification Grammar (TUG), a declarative and reversible grammar formal- ism that brings together Unification Grammar (UG) and ideas of Government & Binding Theory (on)~ The main part of the paper consists in a description of many free word order phenomena of German syn- tax. It will be shown that the use of traces allows for an easier and more elegant way of description than competing approaches like ID/LP-format rules as used e.g. in GPSG and HPSG. Grammkrs writ- ten in the TUG-formallsm can be compiled to a very efficient parser. The occurrence of head movement, wh-movement and scrambling in one sentence does not lead to any decrease in parsing efficiency. 1 Introduction The basic motivation in creating TUG formalism was to capture the empiric knowledge that represents the outcome of at least 15 years' linguistic discussion of German word order, while maintaining the efficiency that is required from a grammar formalism of today's standard. With reference to the basic work of [Len77] on marked and unmarked word order linguists in the generative tradition such as [Thi82], [dB84], [Fau87] and [Cze87] revealed an impreesive list of descrip- tive phenomena that can be appropriately handled by the assumption of s conflgurational, i.e. VP contain- ing description of German word order. Among these phenomena count asymetries in the serialization be- haviour of nominatively marked NPs in passive and the so called "psych" constructio*m*, the account for scrambling phenomena in Acl/ECM Constructions 2 and the observations of [Cze87] wrt. to the voices of double accusative verbs in German. What all these works intend is to pronounce the danger a description of German is likely to run iuto, that "draws immedi- ate conclusions as to the surface position of argumet, t NPH on the basis of their surface cases" ([dB84]:59). t [L~n77] 0howl that v~rlm like w~ndcrn, ge.falle., #din#ca, etc. with non &gentive subjects pat*era with the paaalvized formu of "agentive" verb~ in prefering the unmarked word order indlr¢ct object - subject. [dB84] extends thit ob~scrvation on copular corm*ruction with NP governin~ a4jectivee ~t~e also [dB84] for a thor* outline of tltis problematic ittstte 2 The TUG formalism The basis of TUG is formed by a context free gram- mar that is augmented by PATK ll-styie feature equa- tions. Besides this basis, the main features of TUG are feature typing, mixing of attribute-value-pair and (PROLOG-) ternr unilication, flexible macros, unre~ stricted disjunction attd special rule type~ for argu- ment and head movement, 2.1 Basic rule types As a very simple example we will look at the TUG version of the example grammar in {Shi84] z. 9', type daflnition s => ~. np => f (agr :agrmnt). vp => f (agr : ag'~mt) . v => f (agr : agrmnt). agrmut => f(numbar:number,perton:ptrton). number => {alnguler,plural). permon => {first,necond,thlrd}. % rules • ---> up, …

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