question: reflexive -- everything not in the intersection concode_field_sep PlaceHolder placeHolder concode_field_sep Set<T> intersection concode_elem_sep Set<T> difference concode_elem_sep Set<T> union
target: Set < T > function ( Set < T > arg0 , Set < T > arg1 ) { return difference ( union ( arg0 , arg1 ) , intersection ( arg0 , arg1 ) ) ; }