Time: 215pm-330pm, Friday, April 8, 2011 Place: Room 4102, CUNY Graduate Center, 365 Fifth Ave (34str&35str). Speaker: Prashant Parikh (Penn) Title: Computing Meaning Abstract: I will apply ideas from philosophy of language and semantics to the task of natural language understanding and related tasks like parsing and speech recognition. I will first describe my framework of equilibrium semantics that enables one to derive the meaning of an utterance from first principles by modeling it as a system of interdependent games. The model reduces the problem of natural language understanding to the numerical task of checking which system of linear inequalitiesamong multiple systemsis valid. This presupposes that certain key inputs can be made available. If certain simplifying assumptions are made, the linear inequalities further reduce to a generalization of a Bayesian form for disambiguation commonly used in NLP. This suggests that there is a deeper connection between my framework and work in statistical NLP. Since the game theory adds a dimension of efficient action to the standard assumption of a probability distribution underlying an utterance, it may have greater power than mainstream approaches. It is possible to extend these ideas to syntax and phonology in principle and I conjecture that if such a program were carried out, it would enable one to identify the expressions in an utterance and parse it as well. In the talk, my focus will be on the frameworks computational implications, but I should mention in passing that there are several theoretical implications for the science of language as well. Four of these are a generalization of Fregean compositionality, a derivation of the Gricean conversational maxims, a definition of communication, and a universality principle for games of partial information. Speaker's Bio: Prashant Parikh is a Senior Research Scholar at IRCS at Penn and is the Founder and CEO of Noema, Inc., a natural language software company in New York. He pioneered game-theoretic semantics and pragmatics in the mid-eighties. He is the author of The Use of Language (CSLI Publications, 2001) and Language and Equilibrium (MIT Press, 2010). He did his SB and SM at MIT in the seventies and his PhD at Stanford University with Ken Arrow and Jon Barwise in the eighties.