The grammar framework presented in this paper combines Lexicalized Tree Adjoining Grammar (LTAG) with a (de)compositional frame semantics. We introduce elementary constructions as pairs of elementary LTAG trees and decompositional frames. The linking between syntax and semantics can largely be captured by such constructions since in LTAG, elementary trees represent full argument projections. Substitution and adjunction in the syntax then trigger the unification of the associated semantic frames, which are formally defined as base-labelled feature structures. Moreover, the system of elementary constructions is specified in a metagrammar by means of tree and frame descriptions. This metagrammatical factorization gives rise to a fine-grained decomposition of the semantic contributions of syntactic building blocks, and it allows us to separate lexical from constructional contributions and to carve out generalizations across constructions. In the second half of the paper, we apply the framework to the analysis of directed motion expressions and of the dative alternation in English, two well known examples of the interaction between lexical and constructional meaning.

No abstract

This paper aims to integrate logical operators into frame-based semantics. Frames are semantic graphs that allow lexical meaning to be captured in a fine-grained way but that do not come with a natural way to integrate logical operators such as quantifiers. The approach we propose stems from the observation that modal logic is a powerful tool for describing relational structures, including frames. We use its hybrid logic extension in order to incorporate quantification and thereby allow for inference and reasoning. We integrate our approach into a type theoretic compositional semantics, formulated within Abstract Categorial Grammars. We also show how the key ingredients of hybrid logic, nominals and binders, can be used to model semantic coercion, such as the one induced by the begin predicate. In order to illustrate the effectiveness of the proposed syntax-semantics interface, all the examples can be run and tested with the Abstract Categorial Grammar development toolkit. frames and lexical semanticsFrames emerged as a representation format of conceptual and lexical knowledge (Fillmore 1977;Barsalou 1992;Löbner 2014a). They * This work was supported by the INRIA sabbatical program and by the CRC 991 "The Structure of Representations in Language, Cognition, and Science" funded by the German Research Foundation (DFG). Journal of Language Modelling Vol 5, No 2 (2017), pp. 357-383Laura Kallmeyer et al. are commonly presented as semantic graphs with labelled nodes and edges, such as the one in Figure 1, where nodes correspond to entities (individuals, events, …) and edges correspond to (functional or nonfunctional) relations between these entities. In Figure 1 all relations except part-of are meant to be functional. Structuring the knowledge as frames offers a fine-grained and systematic decomposition of meaning. This conception of frames is however not to be confused with the somewhat simpler FrameNet frames, although the former can help to capture the structural relations of the latter (see Osswald and Van Valin 2014).Frames can be formalized as extended typed feature structures (Petersen 2007; Kallmeyer and Osswald 2013) and specified as models of a suitable logical language, the labelled attribute-value description (LAVD) language. Such a language allows for the composition of lexical frames on the sentential level by means of an explicit syntax-semantics interface (Kallmeyer and Osswald 2013). 1.1 Logical representation of feature structuresThe syntax-semantics interface of (Kallmeyer and Osswald 2013) relies on a formal representation of semantic frames as base-labelled feature structure with types and relations. This definition extends the standard definition of feature structures in two respects. First, in addition to features, proper relations between nodes can be expressed. Moreover, it is not required that every node be accessible from a single root node via a feature path; instead, it is required that every node be accessible from one of the base-labelled nodes. Semantic frames defined in this way can...

No abstract

Abstract. We present a flexible approach for extracting hierarchical classifications from data, which employs the logic of affirmative assertions. The basic observation is that each set of rules induced by the data canonically determines a classificational hierarchy. We give a characterization of how the chosen rule type affects the structure of the induced hierarchy. Moreover, we show how our approach is related to Formal Concept Analysis. The framework is then applied to the induction of hierarchical classifications from an amino acid database. Based on this example, the pros and cons of several types of hierarchies are discussed with respect to criteria such as compactness of representation, suitability for inference tasks, and intelligibility for the human user.

The proper interpretation of prepositions is an important issue for automatic natural language understanding. We present an approach towards PP interpretation as part of a natural language understanding system which has been successfully employed in various NLP tasks for information retrieval and question answering. Our approach is based on the so-called Multi-Net paradigm, a knowledge representation formalism especially designed for the representation of natural language semantics. The paper describes how the information about the semantic interpretation of PPs is represented in the lexicon and in PP interpretation rules and how this information is used during semantic analysis. Moreover, we report on experiments that evaluate the impact of using this information about PP interpretation on the CLEF question answering task.

No abstract

No abstract