Complexity of lexical descriptions and its relevance to partial parsing
Srinivas Bangalore · Scholarly Commons (University of Pennsylvania) · 1997
Complexity of Lexical Descriptions and its Relevance to Partial Parsing Srinivas Bangalore Supervisor: Aravind K. Joshi In this dissertation, we have proposed novel methods for robust parsing that integrate the flexibility of linguistically motivated lexical descriptions with the robustness of statistical techniques. Our thesis is that the computation of linguistic structure can be localized if lexical items are associated with rich descriptions (supertags) that impose complex constraints in a local context. However, increasing the complexity of descriptions makes the number of different descriptions for each lexical item much larger and hence increases the local ambiguity for a parser. This local ambiguity can be resolved by using supertag co-occurrence statistics collected from parsed corpora. We have explored these ideas in the context of Lexicalized Tree-Adjoining Grammar (LTAG) framework wherein supertag disambiguation provides a representation that is an almost parse. We have use...