rdfs:label
rdfs:label is the W3C RDF Schema display-name predicate. This corpus uses it on definition documents (Type, Label, Metadata, Namespace) alongside sd:title: sd:title is the document's title, rdfs:label is the term's name as vocabulary consumers should render it. The Lexicon's definition harvest and editor tooling read it — the Type Definition coherence rule requires it on every defined class.
Why this document exists
rdfs:label belongs to an external namespace, so its defining document lives at w3.org, not in this corpus; this document is the corpus-local registration point for the term. Because rdfs:label is core RDF vocabulary that even the corpus's earliest-reconciled documents carry, the registry seeds the admitting shape as a built-in (sdg:RdfsLabelShape) so it holds from the very first reconcile, independent of ingest order. The constraint below mirrors that seed declaratively, so the corpus states the rule its registry enforces.
Constraint shape
The constraint declares the predicate on sd:Document with no cardinality or datatype restriction — admission, not enforcement. Labels are plain strings today, but multiple or language-tagged labels are legitimate RDFS usage and must not break a document. Expectations about presence (every TypeDefinition should carry one) are enforced by consumption-side coherence rules, not by this shape.