A.2.7:9 - Rationale

Systems applying receiving Methods often need stable organization among system-role kinds before they inspect actual assignments. Keeping that organization as a dependent U.Structure preserves its engineering use without inventing a system-role holon, assignment configuration, second taxonomy, or universal context object.

The families are separate because their laws differ. Substitution is directional. Incompatibility is symmetric under one joint condition. A bundle uses an order-insensitive finite set and an allocation rule. Monotonic qualification belongs to U.SubkindOf; non-monotonic restriction stays residual. One generic hierarchy cannot preserve those distinctions.

Relation realism prevents a document model from becoming the ontology. Direct predicates determine obtaining, and identity laws determine whether the same world-side relation occurrence continues; assertions, policies, and diagrams describe those facts. Slot discipline makes context-local participant domains reviewable and keeps the system-role kind, holder, assignment, predicate, slot, and representation position distinct.