Results 1 to 10 of about 4,278 (200)
Containment of Simple Conjunctive Regular Path Queries [PDF]
Proceedings of the Seventeenth International Conference on Principles of Knowledge Representation and Reasoning, 2020 Testing containment of queries is a fundamental reasoning task in knowledge representation. We study here the containment problem for Conjunctive Regular Path Queries (CRPQs), a navigational query language extensively used in ontology and graph database querying. While it is known that containment of CRPQs is EXPSPACE-complete in general, we focus here
Diego Figueira +5 more
exaly +9 more sources
Regular Queries on Graph Databases [PDF]
, 2015 Graph databases are currently one of the most popular paradigms for storing data. One of the key conceptual differences between graph and relational databases is the focus on navigational queries that ask whether some nodes are connected by paths ...
Reutter, Juan L. +2 more
core +10 more sources
Expressive Path Queries on Graph with Data [PDF]
Logical Methods in Computer Science, 2015 Graph data models have recently become popular owing to their applications, e.g., in social networks and the semantic web. Typical navigational query languages over graph databases - such as Conjunctive Regular Path Queries (CRPQs) - cannot express ...
Pablo Barcelo +2 more
doaj +3 more sources
Conjunctive Regular Path Queries with Capture Groups [PDF]
ACM Transactions on Database Systems, 2022 In practice, regular expressions are usually extended by so-called capture groups or capture variables, which allow to capture a subexpression by a variable that can be referenced in the regular expression in order to describe repetitions of subwords. We investigate how this concept could be used for pattern-based graph querying; i.e., we investigate ...
Markus L Schmid
openaire +3 more sources
Semantic Tree-Width and Path-Width of Conjunctive Regular Path Queries [PDF]
Logical Methods in Computer ScienceWe show that the problem of whether a query is equivalent to a query of tree-width $k$ is decidable, for the class of Unions of Conjunctive Regular Path Queries with two-way navigation (UC2RPQs).
Diego Figueira, Rémi Morvan
doaj +4 more sources
Conjunctive Regular Path Queries under Injective Semantics
Proceedings of the 42nd ACM SIGMOD-SIGACT-SIGAI Symposium on Principles of Database Systems, 2023 We introduce injective semantics for Conjunctive Regular Path Queries (CRPQs), and study their fundamental properties. We identify two such semantics: atom-injective and query-injective semantics, both defined in terms of injective homomorphisms. These semantics are natural generalizations of the well-studied class of RPQs under simple-path semantics ...
Diego Figueira, Miguel Romero
openaire +4 more sources
Converting Instance Checking to Subsumption: A Rethink for Object Queries over Practical Ontologies. [PDF]
Int J Intell Sci, 2015 Efficiently querying Description Logic (DL) ontologies is becoming a vital task in various data-intensive DL applications. Considered as a basic service for answering object queries over DL ontologies, instance checking can be realized by using the most ...
Xu J +4 more
europepmc +2 more sources
The Dichotomy of Evaluating Homomorphism-Closed Queries on Probabilistic Graphs [PDF]
Logical Methods in Computer Science, 2022 We study the problem of query evaluation on probabilistic graphs, namely, tuple-independent probabilistic databases over signatures of arity two. We focus on the class of queries closed under homomorphisms, or, equivalently, the infinite unions of ...
Antoine Amarilli, İsmail İlkan Ceylan
doaj +1 more source
Query rewriting under linear EL knowledge bases [PDF]
, 2016 With the adoption of the recent SPARQL 1.1 standard, RDF databases are capable of directly answering more expressive queries than simple conjunctive queries.
D Calvanese +6 more
core +1 more source
Querying the Unary Negation Fragment with Regular Path Expressions [PDF]
, 2018 The unary negation fragment of first-order logic (UNFO) has recently been proposed as a generalization of modal logic that shares many of its good computational and model-theoretic properties.
Jung, Jean Christoph +3 more
core +1 more source