Each node pulls exactly as its body inside its outermost child, exactly as one body
of its family's mass beyond its own support, and nothing beyond its reach; the root
has no reach, so the zone's far field is exactly c(M_zone) however the generator
splits it. C4 on every band edge, closed-form potential (grid = K phi), Plummer core.
Probe against today, a2, c2, b1 and the tapered draft: ratio, funnel, 12-18 u/s,
far field, split invariance, whole-zone depth, and evaluation cost.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
