#A.6.P:4.1 — Stable lens

Preface node heading:a-6-p-4-1-stable-lens:10707

#Content

A RPR‑pattern SHALL name a stable mathematical “lens” that prevents re‑inventing roles per domain. Examples of lenses (illustrative):

• Kind‑labelled qualified hyperedge / record (default A.6.P lens)
• n‑ary relation with distinguished positions (A.6.5 style)
• kind‑labelled dependence arrow over a base (A.6.6 style)
• span/cospan + declared loss/correspondence notes (Bridge‑like families)
• correspondence relation + repair operations (sync/consistency families)

The lens is a compression device: one stable abstraction that keeps the relation’s arity and polarity stable and makes invariants speakable.