In previous work we studied a new type of DCGs, Datalog grammars, which are inspired on database theory. Their efficiency was shown to be better than that of their DCG counterparts under (terminating) OLDT-resolution. In this article we motivate a variant of Datalog grammars which allows us a meta-grammatical treatment of coordination. This treatment improves in some respects over previous work on coordination in logic grammars, although more research is needed for testing it in other respects.
By examining ellipsis in the context of coordinated structures, which are parallel by definition, and by using extended DLGs, we provide a method in which parallel structures are detected and resolved through syntactic and semantic criteria, and which can be applied to either grammars using different semantic representations- feature structure, @math -calculus, or other. We exemplify using a logic based semantics along the lines of @cite_8 .
@cite_8
2168671000 1568155371 2040110103 1564002882
This paper reports on an empirically based system that automatically resolves VP ellipsis in the 644 examples identified in the parsed Penn Treebank. The results reported here represent the first systematic corpus-based study of VP ellipsis resolution, and the performance of the system is comparable to the best existing systems for pronoun resolution. The methodology and utilities described can be applied to other discourse-processing problems, such as other forms of ellipsis and anaphora resolution.The system determines potential antecedents for ellipsis by applying syntactic constraints, and these antecedents are ranked by combining structural and discourse preference factors such as recency, clausal relations, and parallelism. The system is evaluated by comparing its output to the choices of human coders. The system achieves a success rate of 94.8 , where success is defined as sharing of a head between the system choice and the coder choice, while a baseline recency-based scheme achieves a success rate of 75.0 by this measure. Other criteria for success are also examined. When success is defined as an exact, word-for-word match with the coder choice, the system performs with 76.0 accuracy, and the baseline approach achieves only 14.6 accuracy. Analysis of the individual components of the system shows that each of the structural and discourse constraints used are strong predictors of the antecedent of VP ellipsis. Combinatory Categorial Grammar (CCG) offers a new approach to the theory of natural language grammar. Coordination, relativization, and related prosodic phenomena have been analyzed in CCG in terms of a radically revised notion of surface structure. CCG surface structures do not exhibit traditional notions of syntactic dominance and command, and do not constitute an autonomous level of representation. Instead, they reflect the computations by which a sentence may be realized or analyzed, to synchronously define a predicate-argument structure, or logical form. Surface Structure and Interpretation shows that binding and control can be captured at this level, preserving the advantages of CCG as an account of coordination and unbounded dependency.The core of the book is a detailed treatment of extraction, a focus of syntactic research since the early work of Chomsky and Ross. The topics addressed include the sources of subject-object asymmetries and phenomena attributed to the Empty Category Principle (ECP), asymmetric islands, parasitic gaps, and the relation of coordination and extraction, including their interactions with binding theory. In his conclusion, the author relates CCG to other categorial and type-driven approaches and to proposals for minimalism in linguistic theory.Linguistic Inquiry Monograph No. 30 Abstract This paper presents the application of geometric reasoning to the automatic construction of an assembly partial order from an attributed liaison graph representation of an assembly. The construction is based on the principle of assembly by disassembly and on the extraction of preferred subassemblies. On the basis of accessibility and manipulability criteria, the system first decomposes the given assembly into clusters of mutually inseparable parts. An abstract liaison graph is then generated wherein each cluster of mutually inseparable parts is represented as a supernode. A set of subassemblies is then generated by decomposing the abstract liaison graph into subgraphs, verifying the disassemblability of individual subgraphs, and applying the criteria for selecting preferred subassemblies to the disassemblable subgraphs. The recursive application of this process to the selected subassemblies results in a Hierarchical Partial-Order Graph (HPOG). A HPOG not only provides the precedence relations among assembly operations but also presents the temporal and spatial parallelism for implementing distributed and cooperative assembly. The system is organized under the “cooperative problem solving (CPS)” paradigm. We present a novel ensemble of six methods for improving the efficiency of chart realization. The methods are couched in the framework of Combinatory Categorial Grammar (CCG), but we conjecture that they can be adapted to related grammatical frameworks as well. The ensemble includes two new methods introduced here—feature-based licensing and instantiation of edges, and caching of category combinations—in addition to four previously introduced methods—index filtering, LF chunking, edge pruning based on n-gram scores, and anytime search. We compare the relative contributions of each method using two test grammars, and show that the methods work best in combination. Our evaluation also indicates that despite the exponential worst-case complexity of the basic algorithm, the methods together can constrain the realization problem sufficiently to meet the interactive needs of natural language dialogue systems.