 necessary
    [     sc(burglar,Burglar,[rich(Burglar),expertise(Burglar,Trigger)]=>[casing_joint(Burglar),expertise(Burglar,Trigger)])],
    % conditional
    []).
operator(half_inch(Valuable_item,Trigger,Burglar),
    % prevail
    [     se(valuable_item,Valuable_item,[not_protected(Valuable_item),protected_by(Valuable_item,Trigger)])],
    % necessary
    [     sc(burglar,Burglar,[found_goods(Burglar),expertise(Burglar,Trigger)]=>[rich(Burglar),expertise(Burglar,Trigger)])],
    % conditional
    []).
op