带限制的OWL类型推断 [英] OWL type inference with a restriction

问题描述

我正在使用FaCT ++和琐碎的本体研究Protege 4中OWL限制的概念.假设我有一个Something类的单独的foo:

I am studying the notion of OWL restrictions with Protege 4 using FaCT++ and a trivial ontology. Suppose I have an individual foo of class Something:

:Something a owl:Class.
:foo a :Something, owl:NamedIndividual.

和根据对hasBar属性的限制定义的另一个类:

and another class defined from a restriction on the hasBar property:

:hasBar a owl:ObjectProperty.
:SomethingElse owl:equivalentClass [a owl:Restriction;
                                    owl:onProperty :hasBar;
                                    owl:allValuesFrom :Something].

如果我断言:

:x :hasBar :foo.

为什么不能从中推断出x是SomethingElse(通过foo是Something的事实)?使它起作用的唯一方法是，如果定义了hasBar的range:

why can't I infer from it that x is a SomethingElse (via the fact that foo is a Something)? The only way I can make it work is if the range of hasBar is defined:

:hasBar a owl:ObjectProperty;
        rdfs:range :Something.

但是我想避免这种情况，因为它限制了hasBar的主题(这给我带来了进一步的麻烦).

But I'd like to avoid that, because it puts a constraint on what can be the subject of hasBar (which causes me further trouble).

推荐答案

我认为对实际示例进行推理更简单，让我们考虑以下知识库:

I think it is simpler to reason over real examples, let's consider the following knowledge base:

:eats rdf:type owl:ObjectProperty .

:Vegetable rdf:type owl:Class ;
       rdfs:subClassOf owl:Thing .

:Vegetarian rdf:type owl:Class ;
        owl:equivalentClass [ rdf:type owl:Restriction ;
                              owl:onProperty :eats ;
                              owl:allValuesFrom :Vegetable
                            ] .

:Carrot rdf:type :Vegetable ,
             owl:NamedIndividual .

:John rdf:type owl:NamedIndividual , owl:Thing ;
      :eats :carrot .

与您的示例等效:hasBar是eats，Vegetarian是SomethingElse，Vegetable是Something，foo是carrot，最后x是.

You have some equivalences with your example: hasBar is eats, Vegetarian is SomethingElse, Vegetable is Something, foo is carrot and finally x is John.

现在，您想推断出John是Vegetarian(= x是SomethingElse).

Now you would like to infer that John is a Vegetarian (= x is SomethingElse).

在owl:allValuesFrom下不起作用是有道理的.您在这里所说的是所有素食主义者，如果有一个属性，则必须有蔬菜.因此，您可以推断出carrot是一种蔬菜，假设您首先我会知道约翰是素食主义者.

It makes sense that it doesn't work with an owl:allValuesFrom. What you are saying here is that all instances of vegetarian, if they have a property, they must have Vegetable in range. So from that you could deduce that carrot is a vegetable for example, assuming you would know that John is a vegetarian in the first place.

这在自然语言中也是有道理的:在您的本体论中，您只知道约翰吃胡萝卜，但这并不能自动使他成为素食主义者(非素食人士也吃胡萝卜).

It makes sense in natural language too: In your ontology you only know that John eats a carrot, this doesn't automatically make him a vegetarian (non-vegetarian people eat also carrots).

您可以使用owl:someValuesFrom代替owl:allValuesFrom.这样，您就可以定义每个素食者都有一个吃蔬菜的人.在这种情况下，如果我们知道John吃了胡萝卜，那么根据您对素食主义者概念的定义，推理机会将他归类为素食主义者.

You could use a owl:someValuesFrom instead of a owl:allValuesFrom. This way, you would define every vegetarian has someone that eats some vegetable. In this case if we know that John eats a carrot, therefore he would be classified as vegetarian by the reasoner, based on your definition of the concept vegetarian.

通用(allValuesFrom)和存在(someValuesFrom)限制很难理解，通常没有对或错的解决方案，这主要取决于您要实现的目标.

Universal (allValuesFrom) and existential (someValuesFrom) restrictions are complicated to understand, there is often no right or wrong solution, it mostly depends to what you want to achieve.

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