Presupposition And VP-Ellipsis

We discuss a treatment of VP-ellipsis resolution in DRT in general, and particularly cases where the source clause of the elliptical VP contains presupposition triggers. We propose to restrain VP-elfipsis resolution by presupposition neutralization. We view presupposition as a kind of anaphora, with the ability to accommodate an antecedent if not provided by discourse. 1 I n t r o d u c t i o n In this paper we discuss the treatment of VPellipsis resolution in general, and particularly its interaction with presupposition. We share the opi= nion of those who argue that ellipsis resolution should take place at a semantic level [Dalrymple et al., 1991; Kehler, 1993; Sere, 1993]. We will provide a framework in which ellipsis resolution is constrained by presupposition projection, and furthermore, anaphora and presupposition are represented underspecified in the semantics. The latter postulation is necessary for a proper treatment of VP-ellipsis on the semantic level. The source clause of an elliptical VP often contains presupposition triggers, and resolution of the elided VP asks for presupposition projection in the context of the target elliptical clause. This is an issue which has been neglected in the literature hitherto. The other thesis we put forward in this paper is that VP-ellipsis resolution is constrained by presupposition. Every elided VP is evidently escorted by some presupposition trigger. The cases we will pursue through this paper is the presupposition *This work was partly funded by the German Ministry for Research and Technology (BMFT) under contract 01 IV 101 k/1 (VERBMOBIL). introduced by focusing particles such as too. Of our interest are examples like: (1) John kicked his dog, and Tom did, too. (2) With Betty, John visited her parents, and with MARY, he did, too. Example (1) presupposes that only John owns a dog (in the strict reading), or presupposes that both John and Tom own a dog (in the sloppy reading). Example (2) shows that this strict/sloppy ambiguity also occurs in cases where there is a non-subject parallelism. We use the level of discourse representation for VP-ellipsis resolution, in an extension of Discourse Representation Theory [Kamp, 1981]. For the reconstruction of elided material we adopt a version of Asher's Concept Abstraction mechanism [Asher, 1993]. We furthermore integrate Van der Sandt's presupposition projection algorithm [1992]. Van der Sandt argues that presuppositions are kind of anaphoric expressions which interpretation is strongly influenced by discourse structure. The main difference to pronouns is that presuppositions have more descriptive content, which enables them to accommodate an antecedent, in case not provided by discourse. 2 D R T f r a m e w o r k In this section I will outline a proper framework that integrates anaphora resolution, presupposition projection, and ellipsis resolution. Basically, we will extend Kamp's Discourse Representation Theory slightly, by integrating the treatment of presupposition of Van der Sandt and reference to