Definability problems for graph query languages

Antonopoulos, Timos; Neven, Frank; Servais, Frédéric

doi:10.1145/2448496.2448514

Cited by 21 publications

(29 citation statements)

References 28 publications

(51 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…RPQ-definability is known to be Pspace-complete [3]. We will now prove that RDPQ=-definability is Pspace-complete as well.…”

Section: Queries Using Regular Expres-sions With Equalitymentioning

confidence: 83%

“…The RDPQmem-definability problem on G can be reduced to the RPQ-definability problem on Gaut . The Pspace-completeness of RPQ-definability [3] will then give an Expspace upper bound for RDPQmem-definability. This approach however does not throw light on the role of registers in definability, nor does it give precise bounds in the case where the number of registers is fixed.…”

Section: Lemma 15mentioning

confidence: 99%

“…For graphs without data considered in [3], the solution to RPQ-definability looks at the graph as a finite automaton. This paves the way for using language theoretic tools, which are ultimately based on a pumping argument.…”

Section: Lemma 18mentioning

confidence: 99%

“…In [3], the complexity of the definability problem for graph query languages is studied, but they do not consider data values. Their main result is that definability using regular expressions in Pspace-complete.…”

Section: Introductionmentioning

confidence: 99%

“…They also give upper and lower bounds for various fragments of conjunctive queries based on regular expressions. We do not study conjunctive queries or their fragments but instead give tight bounds for union of conjunctive queries, which also apply to the setting of [3] where there are no data values.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Defining Relations on Graphs

Praveen

Srivathsan

2015

Proceedings of the 34th ACM SIGMOD-SIGACT-SIGAI Symposium on Principles of Database Systems

View full text Add to dashboard Cite

Designing query languages for graph structured data is an active field of research. Evaluating a query on a graph results in a relation on the set of its nodes. In other words, a query is a mechanism for defining relations on a graph. Some relations may not be definable by any query in a given language. This leads to the following question: given a graph, a query language and a relation on the graph, does there exist a query in the language that defines the relation? This is called the definability problem. When the given query language is standard regular expressions, the definability problem is known to be Pspace-complete.The model of graphs can be extended by labeling nodes with values from an infinite domain. These labels induce a partition on the set of nodes: two nodes are equivalent if they are labeled by the same value. Query languages can also be extended to make use of this equivalence. Two such extensions are Regular Expressions with Memory (REM) and Regular Expressions with Equality (REE).In this paper, we study the complexity of the definability problem in this extended model when the query language is either REM or REE. We show that the definability problem is Expspace-complete when the query language is REM, and it is Pspace-complete when the query language is REE. In addition, when the query language is a union of conjunctive queries based on REM or REE, we show coNPcompleteness.

show abstract

“…RPQ-definability is known to be Pspace-complete [3]. We will now prove that RDPQ=-definability is Pspace-complete as well.…”

Section: Queries Using Regular Expres-sions With Equalitymentioning

confidence: 83%

Section: Lemma 15mentioning

confidence: 99%

Section: Lemma 18mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%