Abductive Reasoning with Logic Programs with Negation

Title: Abductive Reasoning with Logic Programs with Negation
Speaker: Prof. Jia-Huai You (University of Alberta, Canada)
Time: 3月20号(星期二)下午3点
Venue: 5号楼3楼计算机科学国家重点实验室报告厅

Abstract:Abductive reasoning subscribes to reasoning processes where explanatory hypotheses are formed and evaluated  with respect to a knowledge base and an observation. Many intelligent tasks, including diagnosis, scientific discovery, legal reasoning, and natural language understanding, have been characterized as abduction.

Logic programming offers an attractive approach to abductive reasoning, partially due to its efficient top-down reasoning mode. Logic programs are extended to allow negation in rule bodies. While this addition has substantially increased the expressive power of logic programs, it also caused a problem for proof procedures; namely the general difficulty in processing negative queries with variables. This is the well-known problem of “problematic quantification patterns.”

In this talk, we present an abductive proof framework, where all programs and queries are processed under a uniform representation. We show that the quantification problem is essentially a problem of solving quantified equations and disequations. Provided that such a reasoner is available, the proposed framework is sound and complete with respect to the predicate completion semantics.

About the Speaker:
Jia-Huai You obtained his PhD from the University of Utah in 1985, and first served on the faculty of Rice University, and then joined the Department of Computing Science at the University of Alberta, where he is now a Professor.His research interests are in logic-based Knowledge Representation and Reasoning, Constraint Satisfaction, Nonmonotonic Logics, and various programming languages for declarative problem solving. Dr. You has published substantially in first-rate international journals and conferences, such as Artificial Intelligence, JCSS, ACM TOCL, JAR, JLP, TCS, IJCAI, PODS, POPL, ICLP, etc. He has served
on the PC of a number of conferences, including IJCAI, AAAI, ECAI, LPNMR, etc. His most recent research interest lies on issues related to integration of SAT, CSP and Answer Set Programming.