Resolving Discourse Deictic Anaphors in Tutorial Dialogues

Most of the anaphoric resolution algorithms developed so far focus on anaphors with NP antecedents, be it inter-sentential or intrasentential. The main focus of this paper is to resolve various other types of anaphors such as discourse deictic anaphors found in computermediated tutorial dialogues on physics. We do this first through a corpus-based study of physics tutoring dialogues. Our approach is to examine the syntactic and semantic environments under which deictic anaphors can occur in the physics discourse and identify the relevant discourse cues, which in turn, are used to formulate a set of constraints and preferences inspired by Centering Theory (Grosz et al. 1995) and the theory of discourse structure (Grosz and Sidner 1986). We propose an algorithm to resolve discourse deictic anaphors in dialogues which is also capable of distinguishing deictic anaphors from individual and expletive anaphors.