Ontology-mediated query answering is a popular paradigm for enriching answers to user queries with background knowledge. For querying the absence of information, however, there exist only few ontology-based approaches. Moreover, these proposals conflate the closed-domain and closed-world assumption, and therefore are not suited to deal with the anonymous objects that are common in ontological reasoning. Many real-world applications, like processing electronic health records (EHRs), also contain a temporal dimension, and require efficient reasoning algorithms. Moreover, since medical data is not recorded on a regular basis, reasoners must deal with sparse data with potentially large temporal gaps. Our contribution consists of two main parts: In the first part we introduce a new closed-world semantics for answering conjunctive queries with negation over ontologies formulated in the description logic ELHb, which is based on the minimal canonical model. We propose a rewriting strategy for dealing with negated query atoms, which shows that query answering is possible in polynomial time in data complexity. In the second part, we extend this minimal-world semantics for answering metric temporal conjunctive queries with negation over the lightweight temporal logic TELHb and obtain similar rewritability and complexity results. This paper is under consideration in Theory and Practice of Logic Programming (TPLP).

中文翻译：

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稀疏 ABox 的时间最小世界语义

本体介导的查询回答是一种流行的范式，用于通过背景知识丰富用户查询的答案。然而，为了查询信息的缺失，只有少数基于本体的方法。此外，这些提议将封闭域和封闭世界假设混为一谈，因此不适合处理本体推理中常见的匿名对象。许多现实世界的应用程序，如处理电子健康记录 (EHR)，也包含时间维度，需要高效的推理算法。此外，由于医疗数据不是定期记录的，推理者必须处理具有潜在大时间间隔的稀疏数据。我们的贡献包括两个主要部分：在第一部分中，我们介绍了一种新的封闭世界语义，用于回答对基于最小规范模型的描述逻辑 ELHb 中制定的本体进行否定的连接查询。我们提出了一种处理否定查询原子的重写策略，这表明在数据复杂度的多项式时间内，查询回答是可能的。在第二部分中，我们扩展了这个最小世界语义，用于在轻量级时间逻辑 TELHb 上用否定回答度量时间连接查询，并获得类似的可重写性和复杂性结果。这篇论文正在逻辑编程理论与实践 (TPLP) 中考虑。这表明在数据复杂度的多项式时间内可以进行查询回答。在第二部分中，我们扩展了这个最小世界语义，用于在轻量级时间逻辑 TELHb 上用否定回答度量时间连接查询，并获得类似的可重写性和复杂性结果。这篇论文正在逻辑编程理论与实践 (TPLP) 中考虑。这表明在数据复杂度的多项式时间内可以进行查询回答。在第二部分中，我们扩展了这个最小世界语义，用于在轻量级时间逻辑 TELHb 上用否定回答度量时间连接查询，并获得类似的可重写性和复杂性结果。这篇论文正在逻辑编程理论与实践 (TPLP) 中考虑。