Lunch at 12:30pm, talk at 1pm, in 148 Fitzpatrick
Title: Introduction to Tree Adjoining Grammars
Abstract: Parsing has traditionally relied on context-free grammars to represent the structure of natural language. Yet some believe that CFGs are inadequate for this purpose, and that natural language is not context-free. Inspired by this concern, researchers in the 1980s introduced a new formalism known as Tree Adjoining Grammar (TAG). TAG is mildly context-sensitive, meaning that it falls between context-free and context-sensitive grammars on the Chomsky hierarchy. TAG generates trees by building them up out of tree fragments using two operations called substitution and adjunction. This talk will give a quick introduction to the formalism.
Bio: Darcey is a 3rd year PhD student in the Computer Science and Engineering department, where she is advised by David Chiang. Her research focuses on probabilistic modeling for NLP. This includes work on factor graph grammars, a new class of models which uses graph grammars to generate probabilistic graphical models. More recently, she has been working on globally normalized alternatives to autoregressive language models.