tailieunhanh - Báo cáo khoa học: "Parametric Types for Typed Attribute-Value Logic"

Parametric polymorphism has been combined with inclusional polymorphism to provide natural type systems for Prolog (DH88), HiLog (YFS92), and coristraint resolution languages (Smo89), and, in linguistics, by HPSG-like grammars to classify lists and sets of linguistic objects (PS94), and by phonologists in representations of hierarchical structure (Kle91). | Parametric Types for Typed Attribute-Value Logic Gerald Penn Universităt Tubingen KI. Wilhelmstr. 113 72074 Tuebingen Germany gpenn@ Abstract Parametric polymorphism has been combined with inclusional polymorphism to provide natural type systems for Prolog DH88 HiLog YFS92 and constraint resolution languages Smo89 and in linguistics by HPSG-like grammars to classify lists and sets of linguistic objects PS94 and by phonologists in representations of hierarchical structure Kle91 . This paper summarizes the incorporation of parametric types into the typed attribute-value logic of Car92 thus providing a natural extension to the type system for ALE CP96 . Following Car92 the concern here is not with models of feature terms themselves but with how to compute with parametric types and what different kinds of information one can represent relative to a signature with parametric types than relative to a signature without them. This enquiry has yielded a more flexible interpretation of parametric types with several specific properties necessary to conform to their current usage by linguists and implementors who work with feature-based formalisms. 1 Motivation Linguists who avail themselves of attributevalue logic normally choose whether to encode information with subtypes or features on the aesthetic basis of what seems intuitively to capture their generalizations better. Linguists working in LFG typically use one implicit type for objects that bear features and other types atoms for only featureless objects. In HPSG the situation is less clear both historically semantic relations for example used to be values of a RELN attribute and are now subtypes of a more general semantic type and synchronically verbs for example are identified as un inverted and non- auxiliaries by two boolean-valued features AUX and INV whereas their form . finite infinitive gerund is identified by a subtype of a single vform type . That it makes or at least should make no