# The Expressive Power of SPARQL

@inproceedings{Angles2008TheEP, title={The Expressive Power of SPARQL}, author={Renzo Angles and Claudio Guti{\'e}rrez}, booktitle={SEMWEB}, year={2008} }

This paper studies the expressive power of SPARQL. The main result is that SPARQL and non-recursive safe Datalog with negation have equivalent expressive power, and hence, by classical results, SPARQL is equivalent from an expressiveness point of view to Relational Algebra. We present explicit generic rules of the transformations in both directions. Among other findings of the paper are the proof that negation can be simulated in SPARQL, that non-safe filters are superfluous, and that current…

## 249 Citations

Negation in SPARQL

- Computer ScienceAMW
- 2016

A core SParQL algebra is identified which could be used instead of the W3C SPARQL algebra and the negation operators are analyzed in terms of their compliance with elementary axioms of set theory.

Semantics and complexity of SPARQL

- Computer ScienceTODS
- 2009

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.

The Multiset Semantics of SPARQL Patterns

- Computer ScienceSEMWEB
- 2016

It is proved that the fragment formed by AND, UNION, OPTIONAL, FILTER, MINUS and SELECT corresponds precisely to both, the intuitive multiset relational algebra (projection, selection, natural join, arithmetic union and except), and the mult iset non-recursive Datalog with safe negation.

Semantics and Expressive Power of Subqueries and Aggregates in SPARQL 1.1

- Computer ScienceWWW
- 2016

An in-depth formal analysis of the semantics and expressive power of these new constructs as defined in the SPARQL 1.1 specification are provided, and hence lay the necessary foundations for the development of robust, scalable and extensible query engines supporting complex numerical and analytics tasks.

The Problem of Correlation and Substitution in SPARQL - Extended Version

- Computer ScienceArXiv
- 2018

This paper presents a formal framework to study why different implementations of SPARQL behave differently when evaluating queries with correlated variables based on Datalog, and shows that at the core of this problem lies the historically troubling notion of logical substitution.

Containment and equivalence of well-designed SPARQL

- Computer SciencePODS
- 2014

A comprehensive complexity analysis of containment and equivalence for several fragments of SPARQL for basic extensions in the form of the UNION operator and/or projection results range from NP-completeness to undecidability.

On Expressibility of Non-Monotone Operators in SPARQL

- Computer ScienceKR
- 2016

This work addresses the problem of expressibility of the full ternary OPTIONAL via the simplified binary version and shows that it is possible, but only with an exponential blowup in the size of the query (under common complexity-theoretic assumptions).

On the Satisfiability Problem of Patterns in SPARQL 1.1

- Computer ScienceAAAI
- 2018

This paper provides a complete analysis of decidability/undecidability of satisfiability problems for SParQL 1.1 patterns and provides a guideline for future SPARQL query language design and implementation.

Foundations of SPARQL query optimization

- Computer ScienceICDT '10
- 2010

While studied in the context of a theoretically motivated set semantics, almost all results carry over to the official, bag-based semantics and therefore are of immediate practical relevance.

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