disjoint union
['disjoint union of', 'disjoint union', 'mandatory qualifier constraint', 'has parts of the class', 'Simpler way to state that A, B, C and D are disjoint using one statement and one item. Multiple statements mean different disjoint relations, thus usage of qualifiers: set value Q23766486, then use P642 as qualifier with disjoint sets as values in P642']