A graphical query language supporting recursion
SIGMOD '87 Proceedings of the 1987 ACM SIGMOD international conference on Management of data
Nondeterministic space is closed under complementation
SIAM Journal on Computing
Modularity of cycles and paths in graphs
Journal of the ACM (JACM)
Graph rewriting: an algebraic and logic approach
Handbook of theoretical computer science (vol. B)
Finding $k$ Disjoint Paths in a Directed Planar Graph
SIAM Journal on Computing
Graph minors. XIII: the disjoint paths problem
Journal of Combinatorial Theory Series B
Journal of the ACM (JACM)
Finding Regular Simple Paths in Graph Databases
SIAM Journal on Computing
Regular path queries with constraints
Journal of Computer and System Sciences
Finding an Even Simple Path in a Directed Planar Graph
SIAM Journal on Computing
A polynomial-time algorithm for finding regular simple paths in outerplanar graphs
Journal of Algorithms
Journal of Combinatorial Theory Series B
Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
Formal-Language-Constrained Path Problems
SIAM Journal on Computing
GraphDB: Modeling and Querying Graphs in Databases
VLDB '94 Proceedings of the 20th International Conference on Very Large Data Bases
Word problems requiring exponential time(Preliminary Report)
STOC '73 Proceedings of the fifth annual ACM symposium on Theory of computing
Answering Regular Path Queries Using Views
ICDE '00 Proceedings of the 16th International Conference on Data Engineering
Reasoning on regular path queries
ACM SIGMOD Record
Parameterized Complexity Theory (Texts in Theoretical Computer Science. An EATCS Series)
Parameterized Complexity Theory (Texts in Theoretical Computer Science. An EATCS Series)
Digraph measures: Kelly decompositions, games, and orderings
Theoretical Computer Science
SoQL: A Language for Querying and Creating Data in Social Networks
ICDE '09 Proceedings of the 2009 IEEE International Conference on Data Engineering
An Automata-Theoretic Approach to Regular XPath
DBPL '09 Proceedings of the 12th International Symposium on Database Programming Languages
Complexity results on labeled shortest path problems from wireless routing metrics
Computer Networks: The International Journal of Computer and Telecommunications Networking
Computing label-constraint reachability in graph databases
Proceedings of the 2010 ACM SIGMOD International Conference on Management of data
Foundations of Semantic Web databases
Journal of Computer and System Sciences
Proceedings of the thirtieth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Adding regular expressions to graph reachability and pattern queries
ICDE '11 Proceedings of the 2011 IEEE 27th International Conference on Data Engineering
Counting beyond a Yottabyte, or how SPARQL 1.1 property paths will prevent adoption of the standard
Proceedings of the 21st international conference on World Wide Web
The complexity of evaluating path expressions in SPARQL
PODS '12 Proceedings of the 31st symposium on Principles of Database Systems
The dag-width of directed graphs
Journal of Combinatorial Theory Series B
Regular path queries on graphs with data
Proceedings of the 15th International Conference on Database Theory
Regular path queries on large graphs
SSDBM'12 Proceedings of the 24th international conference on Scientific and Statistical Database Management
The complexity of regular expressions and property paths in SPARQL
ACM Transactions on Database Systems (TODS) - Invited papers issue
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Regular path queries (RPQs) select vertices connected by some path in a graph. The edge labels of such a path have to form a word that matches a given regular expression. We investigate the evaluation of RPQs with an additional constraint that prevents multiple traversals of the same vertices. Those regular simple path queries (RSPQs) quickly become intractable, even for basic languages such as (aa)* or a*ba*. In this paper, we establish a comprehensive classification of regular languages with respect to the complexity of the corresponding regular simple path query problem. More precisely, we identify for which languages RSPQs can be evaluated in polynomial time, and show that evaluation is NP-complete for languages outside this fragment. We thus fully characterize the frontier between tractability and intractability for RSPQs, and we refine our results to show the following trichotomy: evaluation of RSPQs is either AC0 , NL-complete or NP-complete in data complexity, depending on the language L. The fragment identified also admits a simple characterization in terms of regular expressions. Finally, we also discuss the complexity of deciding whether a language L belongs to the fragment above. We consider several alternative representations of L: DFAs, NFAs or regular expressions, and prove that this problem is NL-complete for the first representation and PSPACE-complete for the other two. As a conclusion we extend our results from edge-labeled graphs to vertex-labeled graphs.