A literal cubic carrier makes the source base layer vanish. This is the
exact finite statement needed when the Case-I theorem is used at the Case-II
cutoff; no global hypothesis y^N ≤ D is involved.
Maximal direct instantiation of the final concrete Case-I theorem at the
Case-II endpoint s=β+1, z=y (odd N).
The Case-I-only premises hbase, hcube, hdom, hcaseITau, hcaseI,
hsdom, hsm1dom, hv2, and hvz are discharged here. The endpoint
provider remains at s'=σ, not at the current endpoint β+1; hence the theorem
does not hide the desired current-s estimate in hEndpoint.
Two genuinely arithmetic endpoint facts remain explicit: the exact real power
identity D^(1/(β+1))=y required by the Case-I API, and y ≤ D/2, required by
its exact min(y,D/2) cutoff contract.