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Hello and welcome to another episode of the RDFox introductory series.
In this episode, we're going to be looking at sub properties in OWL. If you haven't already seen our videos on the Foundations of OWL or Reasoning, or in fact RDFox in general, please do check out those first.
So the specific axioms that we're going to be looking at today infer this ‘subPropertyOf’ relationship between 'has_father' and 'has_parent' and 'has_mother' and has ‘'has_parent'’. What this will do is wherever in our data we find the 'has_father' or 'has_mother' relationships connecting 2 entities, we will also infer the 'has_parent' relationships connecting the same 2 nodes in the same direction.
We can see this depicted in our image to the right where we have a screenshot from the RDFox web console. Here we can see our explicit data, the data we imported from a file shown in dark grey and our new inferred information in light blue. We can see that we have two examples, one of 'has_mother' and one of 'has_father', both connecting 2 entities and in each case those entities are now also connected by the 'has_parent' relationship.
What this enables us to do is to query our data in new and unified ways, not just making it easier to query for these things, but also broadens the scope of the analysis that we're able to do.
Now another important important point to remember about this kind of axiom is this is what is called an existential where we know with without a doubt that wherever we find 'has_father', this is a sub property of 'has_parent', but if we were to find an explicit version of the 'has_parent' relationship, then we would not know whether to infer 'has_father' or 'has_mother'. Because of this, RDFox will give you a warning when inferring this kind of axiom, letting you know that this will infer information in one direction, but not in both. It's absolutely fine and a normal thing to encounter when working in this kind of system, but it's certainly worth being aware of.
If you'd like to learn more about reasoning in RDFox, continue watching the rest of this series. If you'd like to learn more about our axioms or see specific examples in detail, continue through the rest of our workshop material or sign up for our next workshop for free, available on our website.
The team behind Oxford Semantic Technologies started working on RDFox in 2011 at the Computer Science Department of the University of Oxford with the conviction that flexible and high-performance reasoning was a possibility for data-intensive applications without jeopardising the correctness of the results. RDFox is the first market-ready knowledge graph designed from the ground up with reasoning in mind. Oxford Semantic Technologies is a spin-out of the University of Oxford and is backed by leading investors including Samsung Venture Investment Corporation (SVIC), Oxford Sciences Enterprises (OSE) and Oxford University Innovation (OUI).
