115 research outputs found
An efficient graph algorithm for dominance constraints
Dominance constraints are logical descriptions of trees that are widely used in computational linguistics. Their general satisfiability problem is known to be NP-complete. Here we identify normal dominance constraints and present an efficient graph algorithm for testing their satisfiablity in deterministic polynomial time. Previously, no polynomial time algorithm was known
Meaning versus Grammar
This volume investigates the complicated relationship between grammar, computation, and meaning in natural languages. It details conditions under which meaning-driven processing of natural language is feasible, discusses an operational and accessible implementation of the grammatical cycle for Dutch, and offers analyses of a number of further conjectures about constituency and entailment in natural language
Processing underspecified semantic representations in the constraint language for lambda structures
The constraint language for lambda structures (CLLS) is an expressive language of tree descriptions which combines dominance constraints with powerful parallelism and binding constraints. CLLS was introduced as a uniform framework for defining underspecified semantics representations of natural language sentences, covering scope, ellipsis, and anaphora. This article presents saturation-based algorithms for processing the complete language of CLLS. It also gives an overview of previous results on questions of processing and complexity.Liegt nicht vor
Declarative Programming with Intensional Sets in Java Using JSetL
Intensional sets are sets given by a property rather than by enumerating
their elements. In previous work, we have proposed a decision procedure for a
first-order logic language which provides Restricted Intensional Sets (RIS),
i.e., a sub-class of intensional sets that are guaranteed to denote
finite---though unbounded---sets. In this paper we show how RIS can be
exploited as a convenient programming tool also in a conventional setting,
namely, the imperative O-O language Java. We do this by considering a Java
library, called JSetL, that integrates the notions of logical variable, (set)
unification and constraints that are typical of constraint logic programming
languages into the Java language. We show how JSetL is naturally extended to
accommodate for RIS and RIS constraints, and how this extension can be
exploited, on the one hand, to support a more declarative style of programming
and, on the other hand, to effectively enhance the expressive power of the
constraint language provided by the library
Semantics-based Question Generation and Implementation
This paper presents a question generation system based on the approach of semantic rewriting. The state-of-the-art deep linguistic parsing and generation tools are employed to convert (back and forth) between the natural language sentences and their meaning representations in the form of Minimal Recursion Semantics (MRS). By carefully operating on the semantic structures, we show a principled way of generating questions without ad-hoc manipulation of the syntactic structures. Based on the (partial) understanding of the sentence meaning, the system generates questions which are semantically grounded and purposeful. And with the support of deep linguistic grammars, the grammaticality of the generation results is warranted. Further, with a specialized ranking model, the linguistic realizations from the general purpose generation model are further refined for our the question generation task. The evaluation results from QGSTEC2010 show promising prospects of the proposed approach
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