VLog: A Rule Engine for Knowledge Graphs

Abstract

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Restricted Chase Termination for Existential Rules: A Hierarchical Approach and Experimentation

“…Based on the above results, we find that the termination status of 19 (2.71%) ontologies in the collection is open (i.e., they do not belong to 6-safe(Φ MFA ) or RMFC or RMFA). We conducted our tests for membership in RMFA and RMFC using VLog (Carral et al . 2019).…”

Beyond the Grounding Bottleneck: Datalog Techniques for Inference in Probabilistic Logic Programs

“…We use VLog (Urbani, Jacobs, and Krötzsch 2016;Carral et al 2019) to implement the principles introduced in Section 3, and refer to this implementation as vProbLog 3 . We use VLog because it has been shown to be efficient, is open source, supports negation (which is used by some of our transformed rules) and provides very efficient rule execution functions that we can invoke directly.…”

“…We further build upon two well-known techniques from the Datalog community, namely semi-naive evaluation (Abiteboul, Hull, and Vianu 1995), which avoids recomputing the same consequences repeatedly during forward reasoning, and the magic sets transformation (Bancilhon et al 1986;Beeri and Ramakrishnan 1991), which makes forward reasoning query driven. We adapt and extend both techniques to incorporate the formula construction performed by the Tc P operator and implement our approach using VLog (Urbani, Jacobs, and Krötzsch 2016;Carral et al 2019). Our experimental evaluation demonstrates that the resulting vProbLog system enables PLP inference in the pOBDA setting, answering each of the 14 standard queries of the LUBM benchmark (Guo, Pan, and Heflin 2011) over a probabilistic database of 19K facts in a few minutes at most, while most of these are infeasible for the existing ProbLog implementation of Tc P .…”

DaRLing: A Datalog rewriter for OWL 2 RL ontological reasoning under SPARQL queries

“…DLV ∃ (Leone et al 2019) is an effective system for fast query answering over shy, an easily recognizable class of strongly parsimonious programs that strictly generalizes Datalog while preserving its complexity even under conjunctive queries. Among the systems dedicated to ontological query answering in the context of existential rules there are also Graal (Baget et al 2015) and VLog (Carral et al 2019). These systems are not ad-hoc for OWL 2 RL and typically capture more expressive ontologies and then support features such as the skolem and the restricted (standard) chase for reasoning over existential rules.…”