Why I can't use the boolean in SWRL Tab？

[233yun]

I try to write some Inspection rules with swrl, OwlProjetUnit(?x) ^ owlhascoordsystem(?x, ?y) ^ OwlGeomSpacePositionCoordSystem(?y)->owlrule1(?x,true) , owlrule1 is a Inspection rule of OwlProjetUnit.
in Ontology model，owlrule1 is define as a object property of the OwlProjetUnit class, and its range is boolean.
SWRL Tab shows that true is invalid, I am confused.

[martinjoconnor]

An OWL object property cannot have a boolean range. Object properties relate two OWL indiviudals.

[233yun]

Thank you very much for your reply! I set owlrule1 as the data property and solved the problem. Thank you very much for your help!