Title:On Distributive Subalgebras of Qualitative Spatial and Temporal Calculi
Speaker:Professor Sanjiang Li，University of Technology Sydney
Abstract:Qualitative calculi play a central role in representing and reasoning about qualitative spatial and temporal knowledge. This talk introduces and discusses distributive subalgebras of qualitative calculi, which are subalgebras in which (weak) composition distributives over nonempty intersections.
We show for several most popular qualitative calculi that path consistent constraint networks over a distributive subalgebra are always minimal and strongly n-consistent (in a qualitative sense). Moreover, we give a characterisation of distributive subalgebras, which states that the intersection of a set of m ≥ 3 relations in the subalgebra is nonempty if and only if the intersection of every two of these relations is nonempty. We further compute and generate all maximal distributive subalgebras for those qualitative calculi. Lastly, we establish two nice properties which will play an important role in efficient reasoning with constraint networks involving a large number of variables.
This talk is based on the following publications:
 Zhiguo Long, Sanjiang Li. On Distributive Subalgebras of Qualitative Spatial and Temporal Calculi, Proceedings of the Twelfth Conference on Spatial Information Theory (COSIT 2015), Santa Fe, New Mexico, USA, October 12-16, 2015.
 Sanjiang Li, Zhiguo Long, Weiming Liu, Matt Duckham, and Alan Both. On Redundant Topological Constraints. Artificial Intelligence, 2015, 225: 51-78.
Sanjiang Li received his B.Sc. and Ph.D. degrees in mathematics from, respectively, Shaanxi Normal University, in 1996, and Sichuan University, in 2001. He is now a full professor in Centre of Quantum Computation & Intelligent Systems (QCIS), Faculty of Engineering & Information Technology, University of Technology Sydney (UTS). Before joining UTS, he worked in the Department of Computer Science and Technology, Tsinghua University from September 2001 to December 2008. He was an Alexander von Humboldt research fellow at Freiburg University from January 2005 to June 2006; held a Microsoft Research Asia Young Professorship from July 2006 to June 2009; and held an ARC Future Fellowship from January 2010 to December 2013.
His research interests are mainly in spatial reasoning and artificial intelligence. The main objective of his research is to establish expressive representation formalism of spatial knowledge and provide effective reasoning mechanisms. This will contribute significantly to the advancement of knowledge in qualitative spatial reasoning and smart information use in geographical information systems. Some of his most important work has been published in international journals like AIJ and JAIR and international conferences like IJCAI, AAAI, KR, and ECAI.