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Tractable Lineages on Treelike Instances

Antoine Amarilli, Pierre Bourhis, Pierre Senellart
2016 Proceedings of the 35th ACM SIGMOD-SIGACT-SIGAI Symposium on Principles of Database Systems - PODS '16  
This dichotomy relies on recent polynomial bounds on the extraction of planar graphs as minors, and implies lower bounds in non-probabilistic settings, for query evaluation and match counting in subinstance-closed  ...  In our previous work, using different tools, we showed that query evaluation is linear-time on probabilistic databases for arbitrary monadic second-order queries, if we bound the treewidth of the instance  ...  We also thank the anonymous reviewers of PODS 2016 for their valuable comments, in particular for strengthening Theorem 9.7 to tree-depth.  ... 
doi:10.1145/2902251.2902301 dblp:conf/pods/AmarilliBS16 fatcat:skanmavk2vfrfgop3wqq3ebpoe

The Dichotomy of Evaluating Homomorphism-Closed Queries on Probabilistic Graphs [article]

Antoine Amarilli, İsmail İlkan Ceylan
2022 arXiv   pre-print
This dichotomy covers in particular all fragments of infinite unions of conjunctive queries over arity-two signatures, such as negation-free (disjunctive) Datalog, regular path queries, and a large class  ...  Our main result states that the probabilistic query evaluation problem is #P-hard for all unbounded queries from this class.  ...  For instance, it is unknown whether PQE admits a dichotomy for Datalog queries, for regular path queries, or for ontology-mediated queries [Cey17] .  ... 
arXiv:1910.02048v5 fatcat:qnfubo5dn5fm5dl5xhzndr4e6m

Graph Logics with Rational Relations and the Generalized Intersection Problem

Pablo Barcelo, Diego Figueira, Leonid Libkin
2012 2012 27th Annual IEEE Symposium on Logic in Computer Science  
We then prove a dichotomy result for logics combining regular conditions on individual paths and rational relations on paths, by showing that the syntactic form of formulae classifies them into either  ...  The primary motivation comes from the study of logics for querying graph topology, which have recently found numerous applications.  ...  The main building blocks for graph queries are regular path queries, or RPQs [16] ; they are expressions of the form x L → y, where L is a regular language.  ... 
doi:10.1109/lics.2012.23 dblp:conf/lics/BarceloFL12 fatcat:wnixhv57lfat5f5ccz3ll7ir74

The Dichotomy of Evaluating Homomorphism-Closed Queries on Probabilistic Graphs

Antoine Amarilli, İsmail İlkan Ceylan
2022 Logical Methods in Computer Science  
This dichotomy covers in particular all fragments of infinite unions of conjunctive queries over arity-two signatures, such as negation-free (disjunctive) Datalog, regular path queries, and a large class  ...  Our main result states that the probabilistic query evaluation problem is #P-hard for all unbounded queries from this class.  ...  Datalog can in particular be used to express regular path queries (RPQs) and conjunctions of regular path queries with inverses (C2RPQs) [Bar13] .  ... 
doi:10.46298/lmcs-18(1:2)2022 fatcat:wrz4zd7uqfh4ff7vkoe37tzfnq

Enumeration Problems for Regular Path Queries [article]

Wim Martens, Tina Trautner
2017 arXiv   pre-print
Evaluation of regular path queries (RPQs) is a central problem in graph databases.  ...  We define a class of simple transitive expressions that is prominent in practice and for which we can prove two dichotomy-like results: one for simple paths and one for trails paths.  ...  Acknowledgments We are grateful to Phokion Kolaitis for suggesting us to study enumeration problems on simple paths matching RPQs.  ... 
arXiv:1710.02317v1 fatcat:temk4qfm7raq7jgiamqzlxt75m

Enumeration in Data Management (Dagstuhl Seminar 19211)

Endre Boros, Benny Kimelfeld, Reinhard Pichler, Nicole Schweikardt, Michael Wagner
2019 Dagstuhl Reports  
In addition, we aimed to build and disseminate a toolkit for data-centric enumeration problems, including algorithmic techniques, proof techniques, and important indicator problems.  ...  dichotomies for the evaluation problem.  ...  We study RPQ evaluation for simple paths and trails from a parameterized complexity perspective and define a class of simple transitive expressions that is prominent in practice and for which we can prove  ... 
doi:10.4230/dagrep.9.5.89 dblp:journals/dagstuhl-reports/BorosKPS19 fatcat:gfir76niqfhmno2hpj563cwwqe

A Dichotomy for Homomorphism-Closed Queries on Probabilistic Graphs

Antoine Amarilli, İsmail İlkan Ceylan, Jean Christoph Jung, Carsten Lutz
2020 International Conference on Database Theory  
This dichotomy covers in particular all fragments in UCQ∞ such as negation-free (disjunctive) Datalog, regular path queries, and a large class of ontology-mediated queries on arity-two signatures.  ...  As bounded queries in UCQ∞ are already classified by the dichotomy of Dalvi and Suciu [Dalvi and Suciu, 2012], our results and theirs imply a complete dichotomy on PQE for UCQ∞ queries over probabilistic  ...  For any good possible world ω of G with a witnessing simple s, t-path traversing n edges, φ(ω) has a homomorphism from I n+1 e,Π . 2.  ... 
doi:10.4230/lipics.icdt.2020.5 dblp:conf/icdt/AmarilliC20 fatcat:gts3aweo25ej3iawcxgv7ds3b4

A Trichotomy for Regular Simple Path Queries on Graphs [article]

Guillaume Bagan and Angela Bonifati and Benoit Groz
2012 arXiv   pre-print
More precisely, we identify the fragment that is maximal in the following sense: regular simple path queries can be evaluated in polynomial time for every regular language L that belongs to this fragment  ...  Those regular simple path queries (RSPQs) find several applications in practice, yet they quickly become intractable, even for basic languages such as (aa)* or a*ba*.  ...  Regular path queries allow to traverse the same nodes multiple times, whereas regular simple path queries (RSPQs) permit to traverse each vertex only once.  ... 
arXiv:1212.6857v1 fatcat:jrbeti57njbmfcsih5uxozaohi

Performance evaluation of a discovery and scheduling protocol for multihop ad hoc mobile grids

Antônio Tadeu Azevedo Gomes, Artur Ziviani, Luciana dos Santos Lima, Markus Endler
2009 Journal of the Brazilian Computer Society  
In this paper, we propose the integration of resource discovery and scheduling for mobile ad hoc grids into a single protocol called DICHOTOMY (DIscovery and sCHeduling prOTOcol for MobilitY).  ...  To the best of our knowledge, though, the research on these mechanisms for mobile ad hoc grids is still preliminary.  ...  Performance Evaluation We carried out our experiments in testbed and simulation environments, each of them to evaluate a different aspect of the DICHOTOMY protocol.  ... 
doi:10.1590/s0104-65002009000400003 fatcat:nmojrcvngfeapikzsjxl7u3oiu

Performance evaluation of a discovery and scheduling protocol for multihop ad hoc mobile grids

Antônio Tadeu Azevedo Gomes, Artur Ziviani, Luciana dos Santos Lima, Markus Endler
2009 Journal of the Brazilian Computer Society  
In this paper, we propose the integration of resource discovery and scheduling for mobile ad hoc grids into a single protocol called DICHOTOMY (DIscovery and sCHeduling prOTOcol for MobilitY).  ...  To the best of our knowledge, though, the research on these mechanisms for mobile ad hoc grids is still preliminary.  ...  Performance Evaluation We carried out our experiments in testbed and simulation environments, each of them to evaluate a different aspect of the DICHOTOMY protocol.  ... 
doi:10.1007/bf03194510 fatcat:qckipncpcfc6nmedrwgtzkzpwi

XML data exchange

Marcelo Arenas, Leonid Libkin
2005 Proceedings of the twenty-fourth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems - PODS '05  
We then move to query answering, and prove a dichotomy theorem that classifies data exchange settings into those over which query answering is tractable, and those over which it is coNP-complete, depending  ...  on classes of regular expressions used in DTDs.  ...  Acknowledgments We are very grateful to Ron Fagin, Phokion Kolaitis, and Lucian Popa for many helpful discussions during the early stages of this project, and to Pablo Barceló and Wenfei Fan for their  ... 
doi:10.1145/1065167.1065171 dblp:conf/pods/ArenasL05 fatcat:7sbvhte7mnapxnp4w7uwdopz5e

A structural/temporal query language for Business Processes

Daniel Deutch, Tova Milo
2012 Journal of computer and system sciences (Print)  
In particular we propose a query evaluation algorithm of polynomial data complexity that can be applied uniformly to two kind of common queries over processes, namely queries on the structure of the process  ...  We study in details the relationship of the proposed model with previously suggested formalisms for processes modeling and querying.  ...  Regular path expressions. Indirect edges in the query may be annotated by regular expressions.  ... 
doi:10.1016/j.jcss.2011.09.004 fatcat:tdg3lfg4yjfptfi2juoblnxvlm

On the Enumeration Complexity of Unions of Conjunctive Queries [article]

Nofar Carmeli, Markus Kröll
2021 arXiv   pre-print
Nevertheless, we prove that for several classes of queries, free-connexity fully captures the tractable UCQs.  ...  We study the enumeration complexity of Unions of Conjunctive Queries(UCQs).  ...  ACKNOWLEDGMENTS The authors are greatly thankful to Benny Kimelfeld for his advice. The work of Nofar Carmeli was supported by the Irwin and Joan Jacobs Fellowship and by the Google PhD Fellowship.  ... 
arXiv:1812.03831v5 fatcat:35apyblfrbgktocq7n5rbjpmeq

Value joins are expensive over (probabilistic) XML

Evgeny Kharlamov, Werner Nutt, Pierre Senellart
2011 Proceedings of the 4th International Workshop on Logic in Databases - LID '11  
Finally, for TPJ we provide a conceptually simple criterion to check whether a given query is essentially join free.  ...  Moreover, for TPJ queries that have a single join, we show a dichotomy: every query is either essentially join-free, and in this case it is tractable over probabilistic XML, or it is intractable.  ...  It is promising that this dichotomy has a very simple characterization, even more so when it is contrasted with the dichotomy of conjunctive queries over tuple-independent probabilistic databases [10]  ... 
doi:10.1145/1966357.1966366 dblp:conf/lid/KharlamovNS11 fatcat:l5il7bxuffbvxgvva7bffbpojq

An Analytical Study of Large SPARQL Query Logs [article]

Angela Bonifati, Wim Martens, Thomas Timm
2017 arXiv   pre-print
for SPARQL query evaluation, query optimization, tuning, and benchmarking.  ...  With the adoption of RDF as the data model for Linked Data and the Semantic Web, query specification from end- users has become more and more common in SPARQL end- points.  ...  query logs analysed in this paper.  ... 
arXiv:1708.00363v1 fatcat:efphtmyxdnalvjryrmlebru5wq
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