On the complexity of alignment problems in two synchronous grammar formalisms

Authors:
Anders Søgaard
Affiliations:
University of Copenhagen
Venue:
SSST '09 Proceedings of the Third Workshop on Syntax and Structure in Statistical Translation
Year:
2009

Citing 6
Cited 1

Computational Complexity and Natural Language

Computational Complexity and Natural Language
The theory of parsing, translation, and compiling

The theory of parsing, translation, and compiling
Stochastic inversion transduction grammars and bilingual parsing of parallel corpora

Computational Linguistics
Bitext maps and alignment via pattern recognition

Computational Linguistics
Decoding complexity in word-replacement translation models

Computational Linguistics
Syntax-based alignment: supervised or unsupervised?

COLING '04 Proceedings of the 20th international conference on Computational Linguistics

Empirical lower bounds on translation unit error rate for the full class of inversion transduction grammars

IWPT '09 Proceedings of the 11th International Conference on Parsing Technologies

Quantified Score

Hi-index	0.00

Visualization

Abstract

The alignment problem for synchronous grammars in its unrestricted form, i.e. whether for a grammar and a string pair the grammar induces an alignment of the two strings, reduces to the universal recognition problem, but restrictions may be imposed on the alignment sought, e.g. alignments may be 1: 1, island-free or sure-possible sorted. The complexities of 15 restricted alignment problems in two very different synchronous grammar formalisms of syntax-based machine translation, inversion transduction grammars (ITGs) (Wu, 1997) and a restricted form of range concatenation grammars ((2, 2)-BRCGs) (Søgaard, 2008), are investigated. The universal recognition problems, and therefore also the unrestricted alignment problems, of both formalisms can be solved in time O(n6|G|). The complexities of the restricted alignment problems differ significantly, however.