Infer Anonymous class in Protege with the Rules Tab

Question

I would like to infer an anonymous class definition for my Individuals in Protege.

I have a simple Ontology with the Classes Rain NoRain and Scene, The object Property has_weather. My desire is to be able to infer "has_weather(?x, ?noRain), NoRain(?noRain), Scene(?x) -> (has_weather exactly 0 Rain)(?x) which i wrote in the Rules tab, where i can mix SWRL and OWL Expressions.

I am using Pellet Reasoner, however I also tried with OnTop and Hermit and none works. For example if I do the rule the other way around:

`has_weather(?x, ?noRain), (has_weather exactly 0 Rain)(?x), Scene(?x) -> Test(?x)`

It works without problems.

Is the problem, that Protege just can't infer anonymous classes? Is there any workaround? Thank you in Advance!

here is the code to the ontology

<!-- 
///////////////////////////////////////////////////////////////////////////////////////
//
// Object Properties
//
///////////////////////////////////////////////////////////////////////////////////////
 -->




<!-- http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#has_weather -->

<owl:ObjectProperty rdf:about="http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#has_weather">
    <rdfs:subPropertyOf rdf:resource="http://www.w3.org/2002/07/owl#topObjectProperty"/>
</owl:ObjectProperty>



<!-- 
///////////////////////////////////////////////////////////////////////////////////////
//
// Classes
//
///////////////////////////////////////////////////////////////////////////////////////
 -->




<!-- http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#NoRain -->

<owl:Class rdf:about="http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#NoRain">
    <owl:disjointWith rdf:resource="http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#Rain"/>
</owl:Class>



<!-- http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#Rain -->

<owl:Class rdf:about="http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#Rain"/>



<!-- http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#Scene -->

<owl:Class rdf:about="http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#Scene"/>



<!-- 
///////////////////////////////////////////////////////////////////////////////////////
//
// Individuals
//
///////////////////////////////////////////////////////////////////////////////////////
 -->




<!-- http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#NoRain -->

<owl:NamedIndividual rdf:about="http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#NoRain">
    <rdf:type rdf:resource="http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#NoRain"/>
</owl:NamedIndividual>



<!-- http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#Scene -->

<owl:NamedIndividual rdf:about="http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#Scene">
    <rdf:type rdf:resource="http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#Scene"/>
    <has_weather rdf:resource="http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#NoRain"/>
</owl:NamedIndividual>



<!-- 
///////////////////////////////////////////////////////////////////////////////////////
//
// Rules
//
///////////////////////////////////////////////////////////////////////////////////////
 -->

<rdf:Description rdf:about="urn:swrl:var#x">
    <rdf:type rdf:resource="http://www.w3.org/2003/11/swrl#Variable"/>
</rdf:Description>
<rdf:Description rdf:about="urn:swrl:var#noRain">
    <rdf:type rdf:resource="http://www.w3.org/2003/11/swrl#Variable"/>
</rdf:Description>
<rdf:Description>
    <rdf:type rdf:resource="http://www.w3.org/2003/11/swrl#Imp"/>
    <swrl:body>
        <rdf:Description>
            <rdf:type rdf:resource="http://www.w3.org/2003/11/swrl#AtomList"/>
            <rdf:first>
                <rdf:Description>
                    <rdf:type rdf:resource="http://www.w3.org/2003/11/swrl#IndividualPropertyAtom"/>
                    <swrl:propertyPredicate rdf:resource="http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#has_weather"/>
                    <swrl:argument1 rdf:resource="urn:swrl:var#x"/>
                    <swrl:argument2 rdf:resource="urn:swrl:var#noRain"/>
                </rdf:Description>
            </rdf:first>
            <rdf:rest>
                <rdf:Description>
                    <rdf:type rdf:resource="http://www.w3.org/2003/11/swrl#AtomList"/>
                    <rdf:first>
                        <rdf:Description>
                            <rdf:type rdf:resource="http://www.w3.org/2003/11/swrl#ClassAtom"/>
                            <swrl:classPredicate rdf:resource="http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#NoRain"/>
                            <swrl:argument1 rdf:resource="urn:swrl:var#noRain"/>
                        </rdf:Description>
                    </rdf:first>
                    <rdf:rest>
                        <rdf:Description>
                            <rdf:type rdf:resource="http://www.w3.org/2003/11/swrl#AtomList"/>
                            <rdf:first>
                                <rdf:Description>
                                    <rdf:type rdf:resource="http://www.w3.org/2003/11/swrl#ClassAtom"/>
                                    <swrl:classPredicate rdf:resource="http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#Scene"/>
                                    <swrl:argument1 rdf:resource="urn:swrl:var#x"/>
                                </rdf:Description>
                            </rdf:first>
                            <rdf:rest rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#nil"/>
                        </rdf:Description>
                    </rdf:rest>
                </rdf:Description>
            </rdf:rest>
        </rdf:Description>
    </swrl:body>
    <swrl:head>
        <rdf:Description>
            <rdf:type rdf:resource="http://www.w3.org/2003/11/swrl#AtomList"/>
            <rdf:first>
                <rdf:Description>
                    <rdf:type rdf:resource="http://www.w3.org/2003/11/swrl#ClassAtom"/>
                    <swrl:classPredicate>
                        <owl:Restriction>
                            <owl:onProperty rdf:resource="http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#has_weather"/>
                            <owl:qualifiedCardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">0</owl:qualifiedCardinality>
                            <owl:onClass rdf:resource="http://www.semanticweb.org/stefi/ontologies/2021/8/8/untitled-ontology-55#Rain"/>
                        </owl:Restriction>
                    </swrl:classPredicate>
                    <swrl:argument1 rdf:resource="urn:swrl:var#x"/>
                </rdf:Description>
            </rdf:first>
            <rdf:rest rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#nil"/>
        </rdf:Description>
    </swrl:head>
</rdf:Description>

</rdf:RDF>

`

other than that, impossible because an OWL reasoner could infer infinite complex class expressions like `A`, `A and A`, `A and A and A`, ... - so there is no tool that would give you all theoretically possible class expressions. Indeed, what always works is the other way around, i.e. ask whether an individual belongs to `A and A and A ...` in that case it could return `true` — UninformedUser, Sep 09 '21 at 05:49
Hey! Yes I tested it, it works, when I explicitly say for an Individual that it has (has_weather exactly 0 Rain), otherwise it doesn't. But it also works if I tell the reasoner to infer NoRainScene, which is defined like the mentioned expression. For Example what I tried before that is just to not have the relation with the object property, but this doesn't work because of the Open World Assumption, i think — Stefani Guneshka, Sep 09 '21 at 07:59
ah, ok. yes, if you add the class expression directly to the individual it works of course, otherwise it doesn't because of the OWA - and this holds for many thing, negation, max cardinality, etc. — UninformedUser, Sep 09 '21 at 08:27

score 1 · Accepted Answer · answered Sep 08 '21 at 11:05

1

In general a set of axioms has an infinite amout of entailments. See for example this paper. For this reason reasoners restrict inferences to known classes (not anonymous classes). I suspect this holds true for rules as well.

I therefore suggest you add a class NoRain that you set equivalent to has_weather 0 Rain and change your SWRL rule to use the class NoRain.

answered Sep 08 '21 at 11:05

Henriette Harmse

4,167
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Hey ! Thank you , I also though about doing it this way, but I was hoping to somehow avoid having to create a lot of new classes , because the ontology im building is quite big . Nevertheless thank you for your suggestion and I guess this is the way to do it. It also works by the way to have the anonymous expressions in the antecedent, but if i have the classes defined anyway , maybe it doesn't make sense to use anonymous expressions. – Stefani Guneshka Sep 09 '21 at 08:04

Infer Anonymous class in Protege with the Rules Tab

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