@prefix ex: <http://example.org/iadopt/challenge/> .
@prefix iop: <https://w3id.org/iadopt/ont/> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .

ex:denisty a iop:Variable ;
    rdfs:label "density of a pure liquid" ;
    rdfs:comment "mass density of a liquid chemical substance at a specific temperature" ;
    iop:hasConstraint [
      a iop:Constraint ;
      rdfs:label "thermodynamic temperature (required)" ;
      iop:constrains ex:Prop
    ], [
      a iop:Constraint ;
      rdfs:label "purity of liquid (optional)" ;
      iop:constrains ex:Prop
    ] ;
    iop:hasObjectOfInterest ex:OoI ;
    iop:hasProperty ex:Prop .

ex:OoI
    a iop:Entity ;
    rdfs:label "chemical substance" .

ex:Prop
    a iop:Property ;
    rdfs:label "mass density" .