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:- module owl.

%-------------------------------------------------------------------------%
%
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:- interface.
:- import_module rdf.
:- import_module string.

:- func owl(string) = string.
:- mode owl(in) = out is det.
:- mode owl(out) = in is semidet.

:- pred isClass(graph, string).
:- mode isClass(in, in) is semidet.
:- mode isClass(in, out) is multi.

:- pred subClassOf(graph, string, string).
:- mode subClassOf(in, in, in) is semidet.
:- mode subClassOf(in, in, out) is multi.
:- mode subClassOf(in, out, in) is multi.
:- mode subClassOf(in, out, out) is multi.

:- pred sameAs(graph, string, string).
:- mode sameAs(in, in, in) is semidet.
:- mode sameAs(in, out, in) is multi.
:- mode sameAs(in, in, out) is multi.

:- implementation.

owl(S) = "http://www.w3.org/2002/07/owl#" ++ S.

isClass(_, owl("Thing")).
isClass(_, owl("Nothing")).
isClass(G, U) :- property(G, U, rdf("type"), owl("Class")).

sameAs(G, A, B) :-
        A = B;
        property(G, A, owl("sameAs"), B);
        property(G, B, owl("sameAs"), A).