#### Property information

**definition**

x partially overlaps y iff there exists some z such that z is part of x and z is part of y, and it is also the case that neither x is part of y or y is part of x

**editor note**

We would like to include disjointness axioms with part_of and has_part, however this is not possible in OWL2 as these are non-simple properties and hence cannot appear in a disjointness axiom

**first order logic expression**

(forall (?x ?y) (iff (proper_overlaps ?x ?y) (and (overlaps ?x ?y) (not (part_of ?x ?y)) (not (part_of ?y ?x)))))