Relation sumo#disjoint_decomposition (class,class+)  a disjoint_decomposition of a class C is a set of mutually disjoint subclasses of C
  supertype:  relation_to_another_class (pm)
  instance of:  predicate_type (pm)  variable_arity_relation_type (pm)
  related_to:  exhaustiveDecomposition  disjoint
  subtype:  partition (class,class+)  a partition of a class C is a set of mutually disjoint classes (a subclass partition) covering C; each instance of C is instance of exactly one of the subclasses in the partition