# Aggregated Digital Twin **Domain:** Digital Twins / Systems of Systems **Doc Type:** Technical Concept Node **Maturity:** Developed ## Definition An **aggregated digital twin** is a higher-order operational representation composed from multiple subordinate twins or models while preserving enough of their identities and relations to support system-level reasoning. ## Governing Variable Aggregation governs elevation of state: which local variables are summarized, how dependencies are represented and which uncertainty survives compression. ## Material and Computational Manifestation Component twins can contribute to a machine twin; machines to a production line; facilities to a campus; grid, transport and building models to selected urban operations. Aggregation may be hierarchical, federated or task-specific rather than one permanent total model. ## Relation to Governance The aggregated twin allows a higher layer to compare and coordinate systems none of which it completely contains. Its power comes from abstraction, but the same abstraction creates an [[wiki/Asymmetry of Abstraction|asymmetry of abstraction]] between local participants and the coordinating model. ## Constitutional Question and Failure Modes Aggregation can conceal local uncertainty, jurisdiction and minority conditions. A summary that is useful for one decision may be illegitimate for another. Fit, provenance and correction must travel upward with the state they qualify. ## Related Ontology [[wiki/Digital Twin|Digital Twin]] · [[wiki/Digital Twin Interoperability|Digital Twin Interoperability]] · [[wiki/System of Systems|System of Systems]] · [[wiki/Model Fidelity|Model Fidelity]] · [[wiki/Model-Space Sovereignty|Model-Space Sovereignty]]