Notation3 Logic (\nthree) is an extension of RDF that allows the user to write rules introducing new blank nodes to RDF graphs. Many applications (e.g., ontology mapping) rely on this feature as blank nodes -- used directly or in auxiliary constructs -- are omnipresent on the Web. However, the number of fast \nthree reasoners covering this very important feature of the logic is rather limited. On the other hand, there are engines like VLog or Nemo which do not directly support Semantic Web rule formats but which are developed and optimized for very similar constructs: existential rules. In this paper, we investigate the relation between \nthree rules with blank nodes in their heads and existential rules. We identify a subset of \nthree which can be mapped directly to existential rules and define such a mapping preserving the equivalence of \nthree formulae. In order to also illustrate that in some cases \nthree reasoning could benefit from our translation, we then employ this mapping in an implementation to compare the performance of the \nthree reasoners EYE and cwm to VLog and Nemo on \nthree rules and their mapped counterparts. Our tests show that the existential rule reasoners perform particularly well for use cases containing many facts while especially the EYE reasoner is very fast when dealing with a high number of dependent rules. We thus provide a tool enabling the Semantic Web community to directly use existing and future existential rule reasoners and benefit from the findings of this active community.

翻译：摘要：Notation3逻辑（\nthree）是RDF的扩展，允许用户编写规则以向RDF图引入新的空白节点。许多应用（例如本体映射）依赖这一特性，因为空白节点（直接使用或通过辅助结构）在Web上普遍存在。然而，覆盖这一重要逻辑特性的快速\nthree推理引擎数量相当有限。另一方面，存在像VLog或Nemo这样的引擎，它们不直接支持语义网规则格式，但针对非常相似的结构（即存在规则）进行了开发和优化。本文研究了头部含空白节点的\nthree规则与存在规则之间的关系。我们识别了一类可直接映射到存在规则的\nthree子集，并定义了保持\nthree公式等价性的映射。为说明在某些情况下\nthree推理可从我们的转换中受益，我们在实现中采用此映射，比较了\nthree推理器EYE和cwm与VLog和Nemo在\nthree规则及其映射后规则上的性能。测试表明，在包含大量事实的用例中，存在规则推理器表现尤为出色；而处理高依赖性规则时，EYE推理器特别快速。因此，我们提供了一种工具，使语义网社区能直接使用现有及未来的存在规则推理器，并受益于这一活跃社区的研究成果。