@prefix log: <http://www.w3.org/2000/10/swap/log#>.
@prefix : <urn:example:>.

:Ghent a :City.

(_:x) log:onNegativeSurface {
    _:x a :City.
    () log:onNegativeSurface {
        _:x a :HumanCommunity.
    }.
}.

# query
() log:onNegativeSurface {
    :Ghent a :HumanCommunity.
    () log:onNegativeAnswerSurface {
        :Ghent a :HumanCommunity.
    }.
}.
