Statistical Parsing with Context-Free Filtering Grammar

Statistical Parsing with Context-Free Filtering Grammar Michael Demko Master of Science Graduate Department of Computer Science University of Toronto 2007 Statistical parsers that simultaneously generate both phrase-structure and lexical dependency trees have been limited in two important ways: the detection of non-projective dependencies has not been integrated with other parsing decisions, or the constraints between phrase-structure and dependency structure have been overly strict. I develop context-free filtering grammar as a generalization of the more restrictive lexicalized factored parsing model, and I develop for the new grammar formalism a scoring model to resolve parsing ambiguities. I demonstrate the flexibility of the new model by implementing a statistical parser for German, a freer-word-order language exhibiting a mixture of context-free and non-projective behaviours.