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Semantics and complexity of SPARQL
This article identifies a large class of SPARQL patterns, defined by imposing a simple and natural syntactic restriction, where the query evaluation problem can be solved more efficiently and shows that the evaluation problem is coNP-complete for well-designed patterns.
Foundations of semantic web databases
- C. Gutiérrez, Carlos A. Hurtado, A. Mendelzon, Jorge Pérez
- Computer ScienceACM SIGACT-SIGMOD-SIGART Symposium on Principles…
- 14 June 2004
This work proposes a query language with well-defined semantics and study the complexity of query processing, query containment, and simplification of answers, including computational aspects of testing entailment and redundancy.
nSPARQL: A Navigational Language for RDF
- Jorge Pérez, M. Arenas, C. Gutiérrez
- Computer ScienceInternational Workshop on the Semantic Web
- 26 October 2008
This paper proposes the query language nSPARQL that uses nested regular expressions to navigate RDF data and proves that given an RDF graph G and a nested regular expression E, this problem can be solved in time O(|G|@?|E|).
Simple and Efficient Minimal RDFS
On the Semantics of SPARQL
This chapter gives a detailed description of the semantics of this language, a query language called SPARQL, including all the features in the specification by the W3C such as blank nodes in graph patterns and bag semantics for solutions.
Querying semantic web data with SPARQL
Some of the main results about the theory of RDF and SPARQL are surveyed putting emphasis on some research opportunities for the database community.
Minimal Deductive Systems for RDF
This paper presents a minimalist program for RDF, by showing how one can do without several predicates and keywords of the RDF Schema vocabulary, obtaining a simpler language which preserves the…
The Logical Expressiveness of Graph Neural Networks
- P. Barceló, Egor V. Kostylev, M. Monet, Jorge Pérez, Juan L. Reutter, J. Silva
- Computer ScienceInternational Conference on Learning…
- 30 April 2020
The ability of graph neural networks for distinguishing nodes in graphs has been recently characterized in terms of the Weisfeiler-Lehman (WL) test, but this work focuses on Boolean classifiers expressible as formulas in the logic FOC2, a well-studied fragment of first order logic.
Counting beyond a Yottabyte, or how SPARQL 1.1 property paths will prevent adoption of the standard
It is shown that any implementation that adheres to the SPARQL 1.1 specification is doomed to show the same behavior, the key issue being the need for counting solutions imposed by the current specification.
Hate Speech Detection is Not as Easy as You May Think: A Closer Look at Model Validation
- Aymé Arango, Jorge Pérez, Bárbara Poblete
- Computer ScienceAnnual International ACM SIGIR Conference on…
- 18 July 2019
Analysis of experimental methodology and results reported by state-of-the-art systems indicate that supervised approaches achieve almost perfect performance but only within specific datasets, which indicates methodological issues, as well as an important dataset bias.