Boundedness for Unions of Conjunctive Regular Path Queries over Simple Regular Expressions

Fuente: arXiv
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Main Authors: Figueira, Diego, Krishna, S., Mishra, Om Swostik, Padmanabha, Anantha
Format: Preprint
Published: 2024
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author Figueira, Diego
Krishna, S.
Mishra, Om Swostik
Padmanabha, Anantha
author_facet Figueira, Diego
Krishna, S.
Mishra, Om Swostik
Padmanabha, Anantha
contents The problem of checking whether a recursive query can be rewritten as query without recursion is a fundamental reasoning task, known as the boundedness problem. Here we study the boundedness problem for Unions of Conjunctive Regular Path Queries (UCRPQs), a navigational query language extensively used in ontology and graph database querying. The boundedness problem for UCRPQs is ExpSpace-complete. Here we focus our analysis on UCRPQs using simple regular expressions, which are of high practical relevance and enjoy a lower reasoning complexity. We show that the complexity for the boundedness problem for this UCRPQs fragment is $Π^P_2$-complete, and that an equivalent bounded query can be produced in polynomial time whenever possible. When the query turns out to be unbounded, we also study the task of finding an equivalent maximally bounded query, which we show to be feasible in $Π^P_2$. As a side result of independent interest stemming from our developments, we study a notion of succinct finite automata and prove that its membership problem is in NP.
format Preprint
id arxiv_https___arxiv_org_abs_2407_20782
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Boundedness for Unions of Conjunctive Regular Path Queries over Simple Regular Expressions
Figueira, Diego
Krishna, S.
Mishra, Om Swostik
Padmanabha, Anantha
Databases
The problem of checking whether a recursive query can be rewritten as query without recursion is a fundamental reasoning task, known as the boundedness problem. Here we study the boundedness problem for Unions of Conjunctive Regular Path Queries (UCRPQs), a navigational query language extensively used in ontology and graph database querying. The boundedness problem for UCRPQs is ExpSpace-complete. Here we focus our analysis on UCRPQs using simple regular expressions, which are of high practical relevance and enjoy a lower reasoning complexity. We show that the complexity for the boundedness problem for this UCRPQs fragment is $Π^P_2$-complete, and that an equivalent bounded query can be produced in polynomial time whenever possible. When the query turns out to be unbounded, we also study the task of finding an equivalent maximally bounded query, which we show to be feasible in $Π^P_2$. As a side result of independent interest stemming from our developments, we study a notion of succinct finite automata and prove that its membership problem is in NP.
title Boundedness for Unions of Conjunctive Regular Path Queries over Simple Regular Expressions
topic Databases
url https://arxiv.org/abs/2407.20782