Database techniques for the World-Wide Web: a survey
ACM SIGMOD Record
Data on the Web: from relations to semistructured data and XML
Data on the Web: from relations to semistructured data and XML
Modal logic
Foundations of Databases: The Logical Level
Foundations of Databases: The Logical Level
Dynamic Logic
Universality of data retrieval languages
POPL '79 Proceedings of the 6th ACM SIGACT-SIGPLAN symposium on Principles of programming languages
Structural Properties of XPath Fragments
ICDT '03 Proceedings of the 9th International Conference on Database Theory
Efficient processing of joins on set-valued attributes
Proceedings of the 2003 ACM SIGMOD international conference on Management of data
Elements Of Finite Model Theory (Texts in Theoretical Computer Science. An Eatcs Series)
Elements Of Finite Model Theory (Texts in Theoretical Computer Science. An Eatcs Series)
Semantic characterizations of navigational XPath
ACM SIGMOD Record
ACM Transactions on Database Systems (TODS) - Special Issue: SIGMOD/PODS 2004
Structural characterizations of the semantics of XPath as navigation tool on a document
Proceedings of the twenty-fifth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
The Description Logic Handbook
The Description Logic Handbook
Survey of graph database models
ACM Computing Surveys (CSUR)
Relative expressive power of navigational querying on graphs
Proceedings of the 14th International Conference on Database Theory
Linked Data
A Study of a Positive Fragment of Path Queries
The Computer Journal
Querying graph databases with XPath
Proceedings of the 16th International Conference on Database Theory
What we talk about when we talk about graphs
Proceedings of the Joint EDBT/ICDT 2013 Workshops
Trial for RDF: adapting graph query languages for RDF data
Proceedings of the 32nd symposium on Principles of database systems
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Several established and novel applications motivate us to study the expressive power of navigational query languages on graphs, which represent binary relations. Our basic language has only the operators union and composition, together with the identity relation. Richer languages can be obtained by adding other features such as other set operators, projection and coprojection, converse, and the diversity relation. In this paper, we show that, when evaluated at the level of boolean queries with an unlabeled input graph (i.e., a single relation), adding transitive closure to the languages with coprojection adds expressive power, while this is not the case for the basic language to which none, one, or both of projection and the diversity relation are added. In combination with earlier work [10], these results yield a complete understanding of the impact of transitive closure on the languages under consideration.