Identification with the counting component of the actual production sum. The main function, its argument N/a in real arithmetic, and its normalization are left literally unchanged.
Explicit domination by the untruncated beta sum, after whole-a regrouping.
Source-specialized counting estimate, uniform in arbitrary interval cuts, including reversed/empty intervals. No reduced-residue hypothesis is used.
The exact interval in the Pan--Ding--Wang consumer.
With genuine support containment and a reduced residue, neither retained filter removes an effective divisor. The support condition is explicit: arbitrary truncations admit only the domination theorem above.
Exact full-beta regrouping for the source interval whenever its known support-containment threshold holds. This is the only place reducedness is needed; none of the upper bounds require it.