Structural Ownership

Structural Ownership is the meaning, within a whole-part Relationship, that the Whole includes a Part in its structural boundary and is responsible for the Part’s existence, Lifecycle, and Invariants. It denotes semantic responsibility for the Part as part of the Whole, not merely holding a reference to it.

UML 2.5.1 has no independent Metaclass named Structural Ownership. SimpleModeling uses this term to make explicit the Composition semantics that the composite Object is responsible for the existence and storage of its Parts and that a Part is included in at most one composite Whole at a time.

Ordinary ownership may mean legal title, access rights, data stewardship, or organizational responsibility. Structural Ownership is limited instead to whole-part structure in an Object Model.

On the Object side, Structural Ownership identifies the boundary that governs change and Invariants. On the Functional side, reconstruction of immutable values may realize the same meaning, but value containment or function application alone is not called Structural Ownership.

CML (Cozy Modeling Language) represents Structural Ownership through Composition. An ordinary Association, field, reference, or Multiplicity alone does not imply Structural Ownership.

Scala fields, case classes, collections, and nested Types can implement Structural Ownership, but the Scala Type system alone does not determine the domain ownership boundary.

simplemodeling-lib has no single Type that maps one-to-one to Structural Ownership. Collections, Groups, Schemas, and related constructs may be realization elements, while the model’s Composition and Invariants determine the meaning.

Japanese articles and videos use 構造上の所有（Structural Ownership） at first occurrence. The short label 所有 is used later only while the whole-part context remains clear. Uses meaning legal ownership, access rights, or responsibility assignment are not automatically linked to this term.