Datalog^E is the extension of Datalog with existential quantification. While its high expressive power, underpinned by a simple syntax and the support for full recursion, renders it particularly suitable for modern applications on knowledge graphs, query answering (QA) over such language is known to be undecidable in general. For this reason, different fragments have emerged, introducing syntactic limitations to Datalog^E that strike a balance between its expressive power and the computational complexity of QA, to achieve decidability. In this short paper, we focus on two promising tractable candidates, namely Shy and Warded Datalog+/-. Reacting to an explicit interest from the community, we shed light on the relationship between these fragments. Moreover, we carry out an experimental analysis of the systems implementing Shy and Warded, respectively DLV^E and Vadalog.
翻译:Datalog ⁇ E是具有存在性量化的Datalog的延伸。它的高度表达力以简单的语法和对全面递解的支持为基础,使得它特别适合知识图表的现代应用,但一般而言,关于这种语言的问答(QA)是不可更改的。由于这个原因,出现了不同的碎片,对Datalog ⁇ E引入了合成限制,从而平衡其表达力和QA的计算复杂性,从而实现衰减。在这份简短的文件中,我们侧重于两个有希望的可移动候选人,即Shy 和 Warded Datalog+/。为了社区的明确兴趣,我们采取行动,揭示了这些碎片之间的关系。此外,我们分别对Shy和Warded的系统进行了实验性分析,分别是DLV ⁇ E和Vadalog。