The Semantic Web is commonly interpreted under the open-world assumption, meaning that information available (e.g., in a data source) captures only a subset of the reality. Therefore, there is no certainty about whether the available information provides a complete representation of the reality. The broad aim of this article is to contribute a formal study of how to describe the completeness of parts of the Semantic Web stored in RDF data sources. We introduce a theoretical framework allowing augmentation of RDF data sources with statements, also expressed in RDF, about their completeness. One immediate benefit of this framework is that now query answers can be complemented with information about their completeness. We study the impact of completeness statements on the complexity of query answering by considering different fragments of the SPARQL language, including the RDFS entailment regime, and the federated scenario. We implement an efficient method for reasoning about query completeness and provide an experimental evaluation in the presence of large sets of completeness statements.

中文翻译：

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RDF 数据源的完整性管理

语义网通常在开放世界假设下进行解释，这意味着可用信息（例如，在数据源中）仅捕获现实的一个子集。因此，无法确定现有信息是否提供了完全的现实的代表。本文的主要目的是对如何描述存储在 RDF 数据源中的语义 Web 部分的完整性进行正式研究。我们引入了一个理论框架，允许使用同样以 RDF 表示的关于其完整性的语句来增强 RDF 数据源。这个框架的一个直接好处是现在查询答案可以用关于其完整性的信息来补充。我们通过考虑 SPARQL 语言的不同片段（包括 RDFS 蕴涵机制和联合场景）来研究完整性语句对查询回答复杂性的影响。我们实现了一种推理查询完整性的有效方法，并在存在大量完整性语句的情况下提供实验评估。