Grammars and Representation of Grammatical Information. In this area, our research has focussed on Tree-Adjoining Grammars and similar formalisms. These formalisms distinguish themselves from other formalisms investigated in theoretical language processing in that they allow combinations of structures that localize syntactic and semantic dependencies. Our recent work has explored alternate formulations involving use of partially specified structures, retaining several crucial aspects of the original system but yet extending it to make them more appropriate for expressing different grammatical theories. In particular we investigate the use of partial specifications of grammatical structures and the use of inheritance mechanisms.
Natural languages tend to be highly ambiguous.
Our recent work in parsing has focussed on developing techniques to cope with ambiguity. We have developed and continue to investigate representation of compactly representing partial parse structures for substrings of input. Investigations along these lines have also led us to propose parsing methods that apply for a variety of grammar formalisms that have been used in natural language processing. We are interested in investigating the use of semantic constraints to control the parsing of natural language sentences. We are also interested in developing default heuristics and deterministic parsing techniques whose performance is consistent with data on human parsing of sentences.