Tree-adjoining grammar

About: Tree-adjoining grammar is a research topic. Over the lifetime, 2491 publications have been published within this topic receiving 57813 citations.

Unifying Synchronous Tree-Adjoining Grammars and Tree Transducers via Bimorphisms

Abstract: We place synchronous tree-adjoining grammars and tree transducers in the single overarching framework of bimorphisms, continuing the unification of synchronous grammars and tree transducers initiated by Shieber (2004). Along the way, we present a new definition of the tree-adjoining grammar derivation relation based on a novel direct inter-reduction of TAG and monadic macro tree transducers. Tree transformation systems such as tree transducers and synchronous grammars have seen renewed interest, based on a perceived relevance to new applications, such as importing syntactic structure into statistical machine translation models or founding a formalism for speech command and control. The exact relationship among a variety of formalisms has been unclear, with a large number of seemingly unrelated formalisms being independently proposed or characterized. An initial step toward unifying the formalisms was taken (Shieber, 2004) in making use of the formallanguage-theoretic device of bimorphisms, previously used to characterize the tree relations definable by tree transducers. In particular, the tree relations definable by synchronous tree-substitution grammars (STSG) were shown to be just those definable by linear complete bimorphisms, thereby providing for the first time a clear relationship between synchronous grammars and tree transducers.

Coordination in Tree Adjoining Grammars: formalization and implementation

Abstract: In this paper we show that an account for coordination can be constructed using the derivation structures in a lexicalized Tree Adjoining Grammar (LTAG). We present a notion of derivation in LTAGs that preserves the notion of fixed constituency in the LTAG lexicon while providing the flexibility needed for coordination phenomena. We also discuss the construction of a practical parser for LTAGs that can handle coordination including cases of non-constituent coordination.

Basic Gene Grammars and DNA-ChartParser for language processing of Escherichia coli promoter DNA sequences

Abstract: Motivation: The field of ‘DNA linguistics’ has emerged from pioneering work in computational linguistics and molecular biology. Most formal grammars in this field are expressed using Definite Clause Grammars but these have computational limitations which must be overcome. The present study provides a new DNA parsing system, comprising a logic grammar formalism called Basic Gene Grammars and a bidirectional chart parser DNA-ChartParser. Results: The use of Basic Gene Grammars is demonstrated in representing many formulations of the knowledge of Escherichia coli promoters, including knowledge acquired from human experts, consensus sequences, statistics (weight matrices), symbolic learning, and neural network learning. The DNA-ChartParser provides bidirectional parsing facilities for BGGs in handling overlapping categories, gap categories, approximate pattern matching, and constraints. Basic Gene Grammars and the DNAChartParser allowed different sources of knowledge for recognizing E.coli promoters to be combined to achieve better accuracy as assessed by parsing these DNA sequences in real-world data sets. Availability: DNA-ChartParser runs under SICStus Prolog. It and a few examples of Basic Gene Grammars are available at the URL: http://www.dai.ed.ac.uk/∼siu/DNA Contact: {siu,chrism,dr}@dai.ed.ac.uk

Balanced grammars and their languages

Abstract: Balanced grammars are a generalization of parenthesis grammars in two directions. First, several kind of parentheses are allowed. Next, the set of right-hand sides of productions may be an infinite regular language. XML-grammars are a special kind of balanced grammars. This paper studies balanced grammars and their languages. It is shown that there exists a unique minimal balanced grammar equivalent to a given one. Next, balanced languages are characterized through a property of their syntactic congruence. Finally, we show how this characterization is related to previous work of McNaughton and Knuth on parenthesis languages.