George H. L. Fletcher
ABSTRACT
An old idea from the humanistic sciences has it that the language we use not only restricts the manner in which we view the world, but also, in a very real sense, shapes the world around us. This view has deep roots across fields as diverse as anthropology, linguistics, and philosophy. Recently, my colleagues and I have been exploring the interesting ways in which this idea manifests itself in data management. In particular, we have been studying the expressive power of graph query languages at the instance level, where the focus is on characterizing the ability of languages to restrict and shape concrete graph instances, purely in terms of the structure of the instances.
In this talk, I will begin with a brief recap of such structural characterizations of query languages for structured and semi-structured data [4, 7, 8]. I will then introduce the theoretical framework we have been developing for reasoning over graph structured data [1, 2, 3, 6]. Following this, I will discuss how we put the framework to work, with the design of structural indexes for (RDF) graphs [5, 12]. I will also give an overview of our recent results on effectively computing the characterizations on which these index data structures are built [9, 10, 11]. Finally, I will conclude with a discussion of broader applications of the framework in data management and indications for further research.
- G. H. L. Fletcher, M. Gyssens, D. Leinders, J. Van den Bussche, D. Van Gucht, and S. Vansummeren. Similarity and bisimilarity notions appropriate for characterizing indistinguishability in fragments of the calculus of relations. CoRR, abs/1210.2688, 2012.Google Scholar
- G. H. L. Fletcher, M. Gyssens, D. Leinders, J. Van den Bussche, D. Van Gucht, S. Vansummeren, and Y. Wu. Relative expressive power of navigational querying on graphs. In ICDT, pages 197--207, Uppsala, Sweden, 2011. Google ScholarDigital Library
- G. H. L. Fletcher, M. Gyssens, D. Leinders, J. Van den Bussche, D. Van Gucht, S. Vansummeren, and Y. Wu. The impact of transitive closure on the boolean expressiveness of navigational query languages on graphs. In FoIKS, pages 124--143, Kiel, Germany, 2012. Google ScholarDigital Library
- G. H. L. Fletcher, M. Gyssens, J. Paredaens, and D. Van Gucht. On the expressive power of the relational algebra on finite sets of relation pairs. IEEE Trans. Knowl. Data Eng., 21(6):939--942, 2009. Google ScholarDigital Library
- G. H. L. Fletcher, J. Hidders, S. Vansummeren, Y. Luo, F. Picalausa, and P. De Bra. On guarded simulations and acyclic first-order languages. In DBPL, Seattle, 2011.Google Scholar
- G. H. L. Fletcher, J. Van Den Bussche, D. Van Gucht, and S. Vansummeren. Towards a theory of search queries. ACM TODS, 35:28:1--28:33, 2010. Google ScholarDigital Library
- G. H. L. Fletcher, D. Van Gucht, Y. Wu, M. Gyssens, S. Brenes, and J. Paredaens. A methodology for coupling fragments of XPath with structural indexes for XML documents. Inf. Syst., 34(7):657--670, 2009. Google ScholarDigital Library
- M. Gyssens, J. Paredaens, D. Van Gucht, and G. H. L. Fletcher. Structural characterizations of the semantics of XPath as navigation tool on a document. In PODS, pages 318--327, Chicago, IL, USA, 2006. Google ScholarDigital Library
- J. Hellings, G. H. L. Fletcher, and H. Haverkort. Efficient external-memory bisimulation on DAGs. In SIGMOD, pages 553--564, Scottsdale, AZ, USA, 2012. Google ScholarDigital Library
- Y. Luo, Y. de Lange, G. H. L. Fletcher, P. De Bra, J. Hidders, and Y. Wu. Bisimulation reduction of big graphs on MapReduce. In preparation, 2013.Google Scholar
- Y. Luo, G. H. L. Fletcher, J. Hidders, Y. Wu, and P. De Bra. I/O-efficient algorithms for localized bisimulation partition construction and maintenance on massive graphs. CoRR, abs/1210.0748, 2012.Google Scholar
- F. Picalausa, Y. Luo, G. H. L. Fletcher, J. Hidders, and S. Vansummeren. A structural approach to indexing triples. In ESWC, pages 406--421, Heraklion, Greece, 2012. Google ScholarDigital Library
Index Terms
- What we talk about when we talk about graphs
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