Endpoint topology and a conditional certificate

Choose a nonempty declared target set $\mathcal{T}$ of anchored future-null targets. In the selected coordinates write

For each $\zeta =(a,v)\in \mathcal{T}$ and refinement $n$, a realized protocol has declared source coordinates $a_{n,\zeta }$ and receiver coordinates $b_{n,\zeta }$ in the same coordinate space. Write

The coordinate assignments are part of R3–R5; they are not inferred from experiment numbering.

Set

This is a comparison norm in a chosen frame, not a newly derived physical spatial metric.