Answer Counting under Guarded TGDs

IF 0.6 4区数学 Q4 COMPUTER SCIENCE, THEORY & METHODS

Logical Methods in Computer Science Pub Date : 2023-09-14 DOI:10.46298/lmcs-19(3:16)2023

Cristina Feier, Carsten Lutz, Marcin Przybyłko

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引用次数: 2

Abstract

We study the complexity of answer counting for ontology-mediated queries and for querying under constraints, considering conjunctive queries and unions thereof (UCQs) as the query language and guarded TGDs as the ontology and constraint language, respectively. Our main result is a classification according to whether answer counting is fixed-parameter tractable (FPT), W[1]-equivalent, #W[1]-equivalent, #W[2]-hard, or #A[2]-equivalent, lifting a recent classification for UCQs without ontologies and constraints due to Dell et al. The classification pertains to various structural measures, namely treewidth, contract treewidth, starsize, and linked matching number. Our results rest on the assumption that the arity of relation symbols is bounded by a constant and, in the case of ontology-mediated querying, that all symbols from the ontology and query can occur in the data (so-called full data schema). We also study the meta-problems for the mentioned structural measures, that is, to decide whether a given ontology-mediated query or constraint-query specification is equivalent to one for which the structural measure is bounded.

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在守卫tgd下的答案计数

本文研究了本体中介查询和约束下查询的答案计数复杂性，将连接查询及其联合(ucq)作为查询语言，将保护tgd作为本体语言和约束语言。我们的主要结果是根据答案计数是否为固定参数可处理(FPT)、W[1]-等效、#W[1]-等效、#W[2]-硬或# a[2]-等效进行分类，从而提高了Dell等人最近对没有本体和约束的ucq的分类。分类涉及到各种结构度量，即树宽、收缩树宽、星形大小和链接匹配数。我们的结果基于一个假设，即关系符号的数量由一个常数限定，并且在本体中介查询的情况下，来自本体和查询的所有符号都可以出现在数据中(所谓的完整数据模式)。我们还研究了上述结构度量的元问题，即决定给定的本体中介查询或约束查询规范是否等同于结构度量有界的规范。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Logical Methods in Computer Science 工程技术-计算机：理论方法

CiteScore

1.80

自引率

0.00%

发文量

105

审稿时长

6-12 weeks

期刊介绍： Logical Methods in Computer Science is a fully refereed, open access, free, electronic journal. It welcomes papers on theoretical and practical areas in computer science involving logical methods, taken in a broad sense; some particular areas within its scope are listed below. Papers are refereed in the traditional way, with two or more referees per paper. Copyright is retained by the author. Topics of Logical Methods in Computer Science: Algebraic methods Automata and logic Automated deduction Categorical models and logic Coalgebraic methods Computability and Logic Computer-aided verification Concurrency theory Constraint programming Cyber-physical systems Database theory Defeasible reasoning Domain theory Emerging topics: Computational systems in biology Emerging topics: Quantum computation and logic Finite model theory Formalized mathematics Functional programming and lambda calculus Inductive logic and learning Interactive proof checking Logic and algorithms Logic and complexity Logic and games Logic and probability Logic for knowledge representation Logic programming Logics of programs Modal and temporal logics Program analysis and type checking Program development and specification Proof complexity Real time and hybrid systems Reasoning about actions and planning Satisfiability Security Semantics of programming languages Term rewriting and equational logic Type theory and constructive mathematics.