More New OWL Syntax

July 30, 2010

Thus far, I like my New OWL Syntax (though it needs a name). I think the key refinement though is in the counting quantifiers. The slashes just didn’t work, so we have curly brackets with the numbers paired with the right or left one depending on whether you want max, min, or both.

So, a rough grammar

Sub ::= =>
Equiv ::= =
AxiomConnective::= Sub | Equiv
Quantifier ::= Existential | Universal | Counting
Existential ::= <Role>
Universal ::= [Role]
Counting ::= {number Role} 
      | {Role number} 
      |  {number Role number}
Restriction ::= Quantifier Concept
ConjOrDisj ::= Concept (& | v) Concept (parens if needed)
Negation ::=  ~Concept
Concept ::= Restriction | ConjOrDisj | Negation | name
TBoxAxiom ::= Concept AxiomConnective Concept.
ABoxAxiom ::= name:Concept | <name, name>:Role
Role ::= name.

So this gets us ALCQ. An example (some axioms ripped from Koala, I don’t have nominals yet):

Parent = Animal & {1 hasChildren}Thing.
DryEucalyptForest =>Forest.
Koala => Marsupials & <hasHabitat>DryEucalyptForest.
Marsupials => ~Person.
Animal => {1 hasHabitat}Thing & {1 hasGender 1}Thing.
StudentWith3Daughters = Student 
               & ([hasChildren]Female 
                                  & {3 hasChildren 3}Thing)
fluffy:Koala.
<fluffy, sandy>:hasChildren.

I’m not thrilled by my stealing of the nominal constructor ({}). I thought about reusing <> and [] (just adding numbers). This works really well for the existential (since a min N really is N somes, plus a little), but max isn’t that close to the universal for most people. Another problem is that using & and angle brackest means using the corresponding entities in HTML or XML which is a common typing place for me.

Binary and and or can be annoying as well.

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