Composition and Extension
The theorem layer studies how changes in evaluation conditions or system capabilities propagate through the Structural Assurability model.
Expanded evaluator access can enlarge the set of obtainable evidence when resources are held fixed.
Expanded resources can enlarge the set of obtainable evidence when access conditions are held fixed.
Neither result alone implies strict improvement in Structural Assurability. Additional evidence may be immaterial to the claim or may fail to enable a new evidentiary capability.
Capability monotonicity is therefore represented as an explicit condition rather than assumed universally.
A conservative extension establishes strict comparative assurability when the extended system preserves the weaker system's capabilities and adds at least one additional capability.