KERML — Subsetting::/owningType is mandatory

In Clause 8.3.3.3.1 (Overview, Features Abstract Syntax), Figure 18 (Subsetting):

• Subsetting::/owningFeature:Feature[1] narrows the multiplicity inherited from Type::/owningType[0..1] in Clause 8.3.3.1.1 (Overview, Types Abstract Syntax), Figure 10 (Specialization).

• Redefinition::/owningFeature:Feature[0..1] subsets the above with the same name, which is not allowed, and widens the multiplicity back to the one on Type.

This prevents subsettings from being defined without "affecting" the specializing feature (ie, modifying that feature as a model element). Compare to Subclassification, which leaves the inherited multiplicity as is for this purpose, in Clause 8.3.3.2.1 (Overview, 8.3.3.2 Classifiers Abstract Syntax), Figure 16 (Classifiers).