> Full-text translation from Chinese. The original remains authoritative for its research claims; this translation is not independent mathematical verification.

# SRBRD-16
## Buchstab-Row Mass / Upper-Bound Mixed-Flow Closure
### Pair-Buchstab Identity, Cube-Root Semiprime Rows, Dimension-2 Row Sieve, Sifting-Depth Tradeoff and Modular Analytic Closure

**Parent program:** RG-SCP / Reverse Goldbach Structural Closure Program  
**Branch:** SRBRD — Symmetric Root-Bounded Relation Domain  
**Round:** SRBRD-16  
**Date:** 2026-09-30  
**Version:** v0.1  
**Authors:** Neo.K; Aletheia (GPT-5.6 Sol)  
**Type:** Exact Buchstab Decomposition / Row-Sieve Kernel / Analytic Interface Audit  
**Prerequisites:** SRBRD-00 through SRBRD-15  
**Status:** Rough-pair mass, Buchstab loss, semiprime rows and transport correction at the P2 boundary have been assembled into a single exact identity; uniform closure remains incomplete

---

# 0. The Main Question of This Round

SRBRD-15 has obtained:

$$
\boxed{
M_{PP}
=
|\widehat{\mathcal S}_{z_3}|
-
2\sum_{r>z_3}n_r
+
M_{SS},
}
$$

where:

$$
z_3
=
\min\left\{
z\in\mathbb N:
z^3\ge2m-3
\right\}.
$$

This identity has decomposed the ordered Goldbach count into:

1. Cube-root RootRough pair mass;
2. Semiprime least-factor row mass;
3. Semiprime internal transport correction.

But a uniform proof still requires:

$$
\boxed{
\text{lower-bound rough-pair mass}
}
$$

and:

$$
\boxed{
\text{upper-bound semiprime-row mass}.
}
$$

SRBRD-16 further proves:

> Both components can be written as standard sieve / Buchstab-type finite arithmetic objects.

It also obtains a new exact master identity:

$$
\boxed{
M_{PP}
=
|\widehat{\mathcal S}_y|
-
\sum_{\substack{
r\in\mathbb P\\
y<r\le z_3
}}
|\mathcal B_r^{pair}|
-
2
\sum_{\substack{
r\in\mathbb P\\
r>z_3
}}
n_r
+
M_{SS},
}
$$

for any:

$$
2\le y<z_3.
$$

This is the:

# Buchstab–Row–Flow Identity

---

# 1. Canonical Least-Factor Height

For:

$$
x\ge2,
$$

Define the extended least-factor height:

$$
\boxed{
\ell(x)
=
\begin{cases}
+\infty,
&
x\in\mathbb P,
\\
\operatorname{lpf}(x),
&
x\text{ composite}.
\end{cases}
}
$$

Thus a prime is regarded as:

> Having no finite nontrivial root divisor.

---

# 2. RootRough as Least-Factor Threshold

From SRBRD-13:

## Theorem SRBRD-16-T01

$$
\boxed{
\operatorname{RootRough}_z(x)
\Longleftrightarrow
\ell(x)>z.
}
$$

for all:

$$
x\ge2.
$$

This formulation automatically and correctly retains primes with:

$$
x\le z
$$

as displayed above.

---

# 3. Pair Least-Factor Height

For an ordered endpoint:

$$
x\in\widehat\Omega_m,
$$

Let:

$$
y_x=2m-x.
$$

Define:

$$
\boxed{
\rho_m(x)
=
\min
\left(
\ell(x),
\ell(y_x)
\right).
}
$$

If both endpoints are prime:

$$
\rho_m(x)=+\infty.
$$

---

# 4. Pair RootRough Characterization

## Theorem SRBRD-16-T02

$$
\boxed{
x\in\widehat{\mathcal S}_z(m)
\Longleftrightarrow
\rho_m(x)>z.
}
$$

Thus the survivor sets at distinct cutoffs satisfy:

$$
\boxed{
z_1<z_2
\Longrightarrow
\widehat{\mathcal S}_{z_2}
\subseteq
\widehat{\mathcal S}_{z_1}.
}
$$

---

# 5. Pair Buchstab Shell

For a prime:

$$
r,
$$

Define:

$$
\boxed{
\mathcal B_r^{pair}(m)
=
\left\{
x\in\widehat\Omega_m:
\rho_m(x)=r
\right\}.
}
$$

Shells for distinct:

$$
r
$$

are disjoint.

---

# 6. Exact Pair-Buchstab Identity

## Theorem SRBRD-16-T03

If:

$$
2\le y<z,
$$

then:

$$
\boxed{
\widehat{\mathcal S}_y(m)
=
\widehat{\mathcal S}_z(m)
\bigsqcup
\bigsqcup_{\substack{
r\in\mathbb P\\
y<r\le z
}}
\mathcal B_r^{pair}(m).
}
$$

Thus, in cardinality:

$$
\boxed{
|\widehat{\mathcal S}_z|
=
|\widehat{\mathcal S}_y|
-
\sum_{y<r\le z}
|\mathcal B_r^{pair}|.
}
$$

---

# 7. Why T03 Is Buchstab-Like

When the cutoff is raised:

$$
y\to z
$$

as displayed above,

the only reason a survivor is removed is:

> The smallest prime factor first encountered among composite left/right endpoints lies in:
> $$
> (y,z].
> $$

Each state is uniquely assigned by:

$$
\rho_m(x)
$$

to a shell.

Thus there is no inclusion–exclusion multiplicity.

---

# 8. Left / Right / Tie Shell Split

One can further define:

$$
\mathcal B_r^L
=
\{
x:
\ell(x)=r<\ell(2m-x)
\},
$$

$$
\mathcal B_r^R
=
\{
x:
\ell(2m-x)=r<\ell(x)
\},
$$

$$
\mathcal B_r^T
=
\{
x:
\ell(x)=\ell(2m-x)=r
\}.
$$

then:

## Theorem SRBRD-16-T04

$$
\boxed{
\mathcal B_r^{pair}
=
\mathcal B_r^L
\bigsqcup
\mathcal B_r^R
\bigsqcup
\mathcal B_r^T.
}
$$

And:

$$
\boxed{
\mathcal B_r^T\neq\varnothing
\Longrightarrow
r\mid m.
}
$$

This agrees with the earlier center-divisor shared-factor collapse.

---

# 9. Cube-Root Cutoff

Let:

$$
X_m=2m-3,
$$

and:

$$
\boxed{
z_3=z_3(m)
=
\min
\left\{
z:
z^3\ge X_m
\right\}.
}
$$

SRBRD-13：

$$
\widehat{\mathcal S}_{z_3}
$$

endpoints in this set can only be:

- prime；
- semiprime。

---

# 10. Semiprime Row Recalled

For:

$$
r>z_3
$$

prime,

SRBRD-15：

$$
\boxed{
\mathcal R_r(m)
=
\left\{
x\in\widehat{\mathcal S}_{z_3}:
r\mid x,
\quad
x\ge r^2
\right\}.
}
$$

and:

$$
\mathcal R_r
$$

is exactly the set of:

> Semiprime endpoints whose least prime factor is $r$.

Let:

$$
\boxed{
n_r=|\mathcal R_r|.
}
$$

---

# 11. Cofactor Coordinate for a Row

If:

$$
x\in\mathcal R_r,
$$

Write:

$$
\boxed{
x=ru.
}
$$

Since:

$$
x\ge r^2,
$$

we have:

$$
u\ge r.
$$

Also:

$$
x\le X_m,
$$

Thus:

$$
\boxed{
u\le
\left\lfloor
\frac{X_m}{r}
\right\rfloor.
}
$$

---

# 12. Cofactor Primality Is Forced

## Theorem SRBRD-16-T05

If:

$$
r>z_3,
$$

$$
r\le u,
$$

$$
ru\le X_m,
$$

and:

$$
\operatorname{RootRough}_{z_3}(ru),
$$

then:

$$
\boxed{
u\in\mathbb P.
}
$$

---

# 13. T05 Proof

Suppose:

$$
u
$$

is composite.

From:

$$
ru
$$

being RootRough$_{z_3}$,

every prime divisor:

$$
p\mid u
$$

must satisfy:

$$
p>z_3.
$$

Thus:

$$
u>z_3^2.
$$

Also:

$$
r>z_3,
$$

Therefore:

$$
ru>z_3^3.
$$

However:

$$
ru\le X_m\le z_3^3.
$$

a contradiction.

Thus:

$$
u
$$

is prime.

---

# 14. Exact Row Cofactor Formula

From T05:

## Theorem SRBRD-16-T06

$$
\boxed{
n_r
=
\#
\left\{
u:
r\le u\le
\left\lfloor
\frac{X_m}{r}
\right\rfloor,
\quad
\operatorname{RootRough}_{z_3}(ru),
\quad
\operatorname{RootRough}_{z_3}(2m-ru)
\right\}.
}
$$

This formula need not include:

$$
u\in\mathbb P
$$

in the definition.

It follows automatically from RootRough + the cube-root bound.

---

# 15. One-Sided Semiprime Upper Envelope

If the complement RootRough condition is discarded,

then:

$$
u
$$

is still forced to be prime by T05.

Thus:

## Theorem SRBRD-16-T07

$$
\boxed{
n_r
\le
A_r^{one}(m)
}
$$

where:

$$
\boxed{
A_r^{one}(m)
=
\pi
\left(
\left\lfloor
\frac{X_m}{r}
\right\rfloor
\right)
-
\pi(r-1).
}
$$

Therefore:

$$
\boxed{
n_{SP}
=
\sum_{r>z_3}n_r
\le
U_{SP}^{one}
=
\sum_{\substack{
r\in\mathbb P\\
z_3<r\le\sqrt{X_m}
}}
A_r^{one}.
}
$$

---

# 16. Interpretation of $U_{SP}^{one}$

$$
U_{SP}^{one}
$$

is precisely:

> The total number of odd semiprimes in the interval:
> $$
> [3,X_m]
> $$
> whose least prime factor exceeds $z_3$.

It completely ignores the requirement that:

$$
2m-x
$$

must also be RootRough$_{z_3}$.

Thus it is a valid but usually very loose upper envelope.

---

# 17. Finite Audit: One-Sided Envelope

selected controls：

| $m$ | $z_3$ | exact $n_{SP}$ | $U_{SP}^{one}$ |
|---:|---:|---:|---:|
| 100 | 6 | 6 | 10 |
| 199 | 8 | 8 | 16 |
| 496 | 10 | 25 | 63 |
| 1000 | 13 | 35 | 86 |
| 5000 | 22 | 152 | 489 |
| 10000 | 28 | 291 | 1022 |
| 100000 | 59 | 2100 | 8856 |

Thus:

$$
\boxed{
\text{Complement RootRough filtering is a central structure that a row upper bound cannot ignore.}
}
$$

---

# 18. Row Bulk / Frontier Split

For fixed:

$$
r>z_3,
$$

Let:

$$
x=ru,
$$

$$
y=2m-ru.
$$

Define the row bulk:

$$
\boxed{
\mathcal U_r^{bulk}
=
\left\{
u:
r\le u,
\quad
ru\le2m-z_3^2
\right\}.
}
$$

This is equivalent to:

$$
\boxed{
y\ge z_3^2.
}
$$

The row frontier is:

$$
\boxed{
\mathcal U_r^{front}
=
\left\{
u:
2m-z_3^2<ru\le X_m
\right\}.
}
$$

---

# 19. Bulk Root Conditions Become Automatic

For:

$$
u\in\mathcal U_r^{bulk},
$$

and an odd prime:

$$
p\le z_3,
$$

Since:

$$
ru\ge r^2>z_3^2\ge p^2,
$$

and:

$$
2m-ru\ge z_3^2\ge p^2,
$$

the root conditions for:

$$
p
$$

are entirely automatic on both sides.

---

# 20. Exact Row-Bulk Residue Sieve

## Theorem SRBRD-16-T08

For:

$$
u\in\mathcal U_r^{bulk},
$$

we have:

$$
\boxed{
ru
\text{ RootRough}_{z_3}
}
$$

if and only if, for every odd prime:

$$
p\le z_3,
$$

$$
\boxed{
u\not\equiv0\pmod p.
}
$$

At the same time:

$$
\boxed{
2m-ru
\text{ RootRough}_{z_3}
}
$$

if and only if:

$$
\boxed{
u
\not\equiv
2m\,r^{-1}
\pmod p.
}
$$

Since:

$$
r>z_3,
$$

Thus:

$$
r^{-1}\pmod p
$$

always exists.

---

# 21. Local Sieve Dimension

For an odd prime:

$$
p\le z_3,
$$

the number of residue classes excluded by the row bulk is:

$$
\boxed{
\nu_m(p)
=
\begin{cases}
1,
&
p\mid m,
\\
2,
&
p\nmid m.
\end{cases}
}
$$

For if:

$$
p\mid m,
$$

then:

$$
2m r^{-1}\equiv0\pmod p.
$$

the two forbidden residues collapse.

---

# 22. Row Sieve Dimension Theorem

## Theorem SRBRD-16-T09

Every semiprime row bulk:

$$
\mathcal R_r^{bulk}
$$

has the same local-dimension profile:

$$
\boxed{
\nu_m(p)\in\{1,2\}.
}
$$

The residue locations vary with:

$$
r
$$

as displayed above,

but, for each:

$$
p
$$

the forbidden-class cardinality is determined only by:

$$
p\mid m
$$

as displayed above.

Thus, at generic:

$$
p\nmid m
$$

positions, this is a:

# Dimension-2 Sieve

---

# 23. Row Frontier Size

The row frontier corresponds to:

$$
3\le y<z_3^2.
$$

When:

$$
u
$$

increases by:

$$
2,
$$

Since:

$$
u
$$

is odd,

$$
y=2m-ru
$$

decreases by:

$$
2r.
$$

Thus:

## Theorem SRBRD-16-T10

$$
\boxed{
|\mathcal R_r^{front}|
\le
1+
\left\lfloor
\frac{
z_3^2-3
}{
2r
}
\right\rfloor.
}
$$

This is an entirely elementary frontier capacity bound.

---

# 24. Total Frontier Envelope

Define:

$$
\boxed{
F_{SP}^{front}(m)
=
\sum_{\substack{
r\in\mathbb P\\
z_3<r\le\sqrt{X_m}
}}
\left[
1+
\left\lfloor
\frac{
z_3^2-3
}{
2r
}
\right\rfloor
\right].
}
$$

then:

$$
\boxed{
n_{SP}^{front}
\le
F_{SP}^{front}.
}
$$

---

# 25. Frontier Finite Audit

| $m$ | exact $n_{SP}$ | exact frontier rows | crude frontier bound |
|---:|---:|---:|---:|
| 1000 | 35 | 6 | 28 |
| 5000 | 152 | 13 | 92 |
| 10000 | 291 | 12 | 160 |
| 100000 | 2100 | 47 | 695 |

The frontier is not zero,

but finite evidence shows that the main semiprime mass is in the bulk.

---

# 26. Abstract Row Upper-Sieve Provider

For each:

$$
r>z_3,
$$

Define any rigorous provider:

$$
\boxed{
U_r^{bulk}
\ge
|\mathcal R_r^{bulk}|.
}
$$

From T10:

$$
\boxed{
n_r
\le
U_r^{bulk}
+
F_r^{front},
}
$$

where:

$$
F_r^{front}
=
1+
\left\lfloor
\frac{
z_3^2-3
}{
2r
}
\right\rfloor.
$$

Thus:

## Theorem SRBRD-16-T11

$$
\boxed{
n_{SP}
\le
\sum_{r>z_3}
U_r^{bulk}
+
F_{SP}^{front}.
}
$$

---

# 27. Why Upper Sieve Is the Natural Row Tool

The row bulk requires only:

> An upper bound on integers avoiding a set of local residue classes.

This is the direction in which classical upper-bound sieves excel.

More importantly:

$$
\boxed{
\text{We do not require the row sieve to prove that two primes exist simultaneously.}
}
$$

It requires only:

$$
\boxed{
\text{upper-bound semiprime contamination capacity}.
}
$$

This differs from a direct binary-Goldbach lower bound.

---

# 28. Pair Survivor Lower Bound Is Harder

On the other hand,

a lower bound on:

$$
|\widehat{\mathcal S}_{z_3}|
$$

requires a dimension-2 lower sieve.

The cube-root cutoff:

$$
z_3
\asymp
X_m^{1/3}
$$

lies precisely in the difficult region for classical lower sieves.

---

# 29. Sieve Parameter

Classical beta / DHR sieves usually use:

$$
\boxed{
s
=
\frac{\log D}{\log z},
}
$$

where:

- $z$: Sifting cutoff;
- $D$: Available sieve level.

For an interval-like sequence,

the natural distribution level is at most approximately the scale:

$$
D=X_m^{1-o(1)}
$$

as displayed above.

Thus, at the cutoff:

$$
z=X_m^{1/u}
$$

we have:

$$
\boxed{
s\approx u.
}
$$

---

# 30. External Dimension-2 Sifting Limit

The published sifting limit of the Diamond–Halberstam–Richert dimension-2 sieve is approximately:

$$
\boxed{
\beta_2\approx4.266.
}
$$

That is, for the standard lower-bound sieve to enter the positive lower-main-term regime,

it requires roughly:

$$
\boxed{
s>\beta_2.
}
$$

This is an external sieve benchmark, not an SRBRD theorem.

---

# 31. Cube-Root Boundary vs DHR Limit

P2 boundary：

$$
z_3\asymp X_m^{1/3}.
$$

If:

$$
D\asymp X_m,
$$

then:

$$
\boxed{
s\approx3.
}
$$

However:

$$
3<4.266.
$$

Thus:

## External Barrier Observation

At the natural level, the standard dimension-2 DHR lower sieve cannot directly

provide its usual positive lower main term for the cube-root P2 boundary.

---

# 32. This Is Not an Impossibility Theorem

This does not mean:

$$
\boxed{
|\widehat{\mathcal S}_{z_3}|
}
$$

cannot be lower-bounded by other methods.

Nor does it mean:

$$
\boxed{
\text{SRBRD cannot succeed}.
}
$$

It means only:

> The most direct classical route of treating the P2 boundary as a standard dimension-2 sieve to obtain a lower bound
> encounters the known sifting-limit obstacle.

---

# 33. Sieve-Depth / Factor-Depth Tradeoff

Take the general cutoff:

$$
z_h
\asymp
X_m^{1/(h+1)}.
$$

SRBRD-12：

$$
\operatorname{RootRough}_{z_h}(x)
$$

For:

$$
x\le X_m
$$

forces:

$$
\boxed{
\Omega_{\mathrm{mult}}(x)\le h.
}
$$

At the same time, the natural sieve parameter is:

$$
\boxed{
s\approx h+1.
}
$$

---

# 34. Tradeoff Table

| cutoff scale | max factor count | division depth | sieve parameter |
|---|---:|---:|---:|
| $X^{1/2}$ | $1$ | $0$ | $\approx2$ |
| $X^{1/3}$ | $2$ | $\le1$ | $\approx3$ |
| $X^{1/4}$ | $3$ | $\le2$ | $\approx4$ |
| $X^{1/5}$ | $4$ | $\le3$ | $\approx5$ |

Dimension-2 DHR lower positivity requires approximately:

$$
s>4.266.
$$

Thus the most natural direct entry into the positive lower-sieve regime is near:

$$
\boxed{
X^{1/5}
}
$$

as displayed above,

That is:

$$
\boxed{
P_4\text{ boundary},
}
$$

not:

$$
P_2.
$$

---

# 35. Interpretation

This explains precisely why:

> Moving directly from an ordinary dimension-2 lower sieve to the prime / semiprime boundary is not easy.

If the cutoff is lowered to:

$$
X^{1/5},
$$

the lower sieve is more comfortable,

but a survivor endpoint may then have:

$$
4
$$

prime factors.

Thus one must:

$$
\boxed{
\text{First obtain mass at a lower cutoff,
then use Buchstab / cofactor decomposition to move layer by layer to the cube-root boundary.}
}
$$

---

# 36. Two-Cutoff Strategy

Choose:

$$
2\le y<z_3.
$$

Ideally:

$$
y
\asymp
X_m^{1/u},
$$

where:

$$
u>\beta_2.
$$

For example, conceptually:

$$
u\approx5.
$$

First obtain, for:

$$
\widehat{\mathcal S}_y
$$

a dimension-2 lower bound.

Then use T03:

$$
|\widehat{\mathcal S}_{z_3}|
=
|\widehat{\mathcal S}_y|
-
\sum_{y<r\le z_3}
|\mathcal B_r^{pair}|.
$$

This is:

# Sieve → Buchstab Descent

---

# 37. Exact Buchstab–Row–Flow Identity

SRBRD-15：

$$
M_{PP}
=
|\widehat{\mathcal S}_{z_3}|
-
2\sum_{r>z_3}n_r
+
M_{SS}.
$$

Substituting T03:

## Theorem SRBRD-16-T12

For any:

$$
2\le y<z_3,
$$

$$
\boxed{
M_{PP}
=
|\widehat{\mathcal S}_y|
-
\sum_{\substack{
r\in\mathbb P\\
y<r\le z_3
}}
|\mathcal B_r^{pair}|
-
2\sum_{\substack{
r\in\mathbb P\\
r>z_3
}}
n_r
+
M_{SS}.
}
$$

This is the main theorem of this round.

---

# 38. Four Modules of T12

T12 decomposes the ordered Goldbach count into:

### Module A — Coarse Rough Mass

$$
|\widehat{\mathcal S}_y|.
$$

### Module B — Buchstab Descent Loss

$$
\sum_{y<r\le z_3}
|\mathcal B_r^{pair}|.
$$

### Module C — P2 Semiprime Contamination

$$
2\sum_{r>z_3}n_r.
$$

### Module D — Internal Transport Rescue

$$
M_{SS}.
$$

The roles of these four components are clear.

---

# 39. Modular Lower-Bound Closure

Suppose there are proof-admissible providers:

$$
\boxed{
L_y
\le
|\widehat{\mathcal S}_y|,
}
$$

$$
\boxed{
|\mathcal B_r^{pair}|
\le
U_r^{B},
}
$$

$$
\boxed{
n_r
\le
U_r^{row},
}
$$

$$
\boxed{
L_{SS}
\le
M_{SS}.
}
$$

then:

## Theorem SRBRD-16-T13

$$
\boxed{
M_{PP}
\ge
L_y
-
\sum_{y<r\le z_3}U_r^B
-
2\sum_{r>z_3}U_r^{row}
+
L_{SS}.
}
$$

---

# 40. Buchstab–Row–Flow Closure Criterion

## Corollary SRBRD-16-C01

If:

$$
\boxed{
L_y
-
\sum_{y<r\le z_3}U_r^B
-
2\sum_{r>z_3}U_r^{row}
+
L_{SS}
>0,
}
$$

then:

$$
\boxed{
R_G^{-}(2m)>0.
}
$$

This is currently the most complete modular analytic closure contract.

---

# 41. Provider Assignment

The most natural tool assignment:

### $L_y$

A dimension-2 lower sieve.

### $U_r^B$

Buchstab shell upper sieve / least-factor decomposition.

### $U_r^{row}$

A dimension-2 upper sieve on the cofactor row bulk + an explicit frontier.

### $L_{SS}$

SRBRD-15：

- row deficiency；
- block deficiency；
- center-divisor lock；
- transport matching。

This deliberately makes it so that:

$$
\boxed{
\text{the lower-bound sieve works only at the lower cutoff }y,
}
$$

while near the cube-root boundary the main tools are:

$$
\boxed{
\text{upper bounds + exact transport identities}.
}
$$

---

# 42. Finite Audit: $m=1000$

$$
X_m=1997.
$$

cube-root cutoff：

$$
z_3=13.
$$

Take the fifth-root-scale integer:

$$
y=5.
$$

exact：

$$
|\widehat{\mathcal S}_y|=268,
$$

Buchstab loss：

$$
132,
$$

Thus:

$$
|\widehat{\mathcal S}_{z_3}|=136.
$$

semiprime：

$$
n_{SP}=35.
$$

internal：

$$
M_{SS}=8.
$$

Therefore:

$$
\boxed{
M_{PP}
=
268-132-70+8
=
74.
}
$$

reduced：

$$
R_G^{-}(2000)=37.
$$

---

# 43. $m=1000$ Buchstab Shell Distribution

For:

$$
y=5,
\quad
z_3=13,
$$

exact pair losses：

$$
|\mathcal B_7^{pair}|=76,
$$

$$
|\mathcal B_{11}^{pair}|=34,
$$

$$
|\mathcal B_{13}^{pair}|=22.
$$

Sum:

$$
\boxed{
132.
}
$$

This proves that the descent loss is indeed decomposed disjointly by least-factor shells.

---

# 44. Finite Audit: $m=5000$

$$
X_m=9997,
$$

$$
z_3=22.
$$

Take:

$$
y=7.
$$

exact：

$$
|\widehat{\mathcal S}_y|=954,
$$

Buchstab loss：

$$
430,
$$

$$
|\widehat{\mathcal S}_{z_3}|=524.
$$

semiprime：

$$
n_{SP}=152.
$$

internal：

$$
M_{SS}=34.
$$

Thus:

$$
\boxed{
M_{PP}
=
954-430-304+34
=
254.
}
$$

That is:

$$
R_G^{-}(10000)=127.
$$

---

# 45. $m=5000$ Shell Distribution

$$
|\mathcal B_{11}^{pair}|=172,
$$

$$
|\mathcal B_{13}^{pair}|=120,
$$

$$
|\mathcal B_{17}^{pair}|=76,
$$

$$
|\mathcal B_{19}^{pair}|=62.
$$

Total:

$$
\boxed{
430.
}
$$

---

# 46. Larger Two-Cutoff Controls

### $m=10000$

$$
z_3=28,
$$

fifth-root-scale：

$$
y=8.
$$

$$
|\widehat{\mathcal S}_y|=1908,
$$

$$
|\widehat{\mathcal S}_{z_3}|=954,
$$

loss：

$$
954.
$$

$$
n_{SP}=291,
$$

$$
M_{SS}=90,
$$

Thus:

$$
\boxed{
M_{PP}=462.
}
$$

### $m=100000$

$$
z_3=59,
$$

$$
y=12.
$$

$$
|\widehat{\mathcal S}_y|=15584,
$$

$$
|\widehat{\mathcal S}_{z_3}|=6358,
$$

loss：

$$
9226.
$$

$$
n_{SP}=2100,
$$

$$
M_{SS}=676,
$$

Thus:

$$
\boxed{
M_{PP}=2834.
}
$$

---

# 47. One-Sided Row Envelope No-Go

If one uses only:

$$
U_{SP}^{one},
$$

then the crude lower bound is:

$$
M_{PP}
\ge
|\widehat{\mathcal S}_{z_3}|
-
2U_{SP}^{one}
+
L_{SS}.
$$

Even if one temporarily uses the exact:

$$
L_{SS}=M_{SS},
$$

selected：

### $m=1000$

$$
136-2(86)+8=-28.
$$

### $m=5000$

$$
524-2(489)+34=-420.
$$

### $m=10000$

$$
954-2(1022)+90=-1000.
$$

### $m=100000$

$$
6358-2(8856)+676=-10678.
$$

Thus:

$$
\boxed{
\text{A row upper envelope ignoring opposite-endpoint RootRough is simply insufficient.}
}
$$

---

# 48. Exact Location of the Needed Gain

If a uniform proof follows T13,

what actually needs strengthening is not:

$$
\boxed{
\text{one-sided semiprime counting}.
}
$$

but:

$$
\boxed{
\text{two-form row sieve}
}
$$

that is, simultaneously requiring:

$$
ru
$$

and:

$$
2m-ru
$$

to avoid small root divisors.

In the row bulk, this is exactly T08's dimension-2 residue system.

---

# 49. Why This Is Better Localized Than Original Goldbach

Original Goldbach:

$$
x,
\quad
2m-x
$$

both must be prime simultaneously.

Row problem:

$$
ru,
\quad
2m-ru
$$

requires only:

> An upper bound on cofactor candidates that pass the RootRough sieve.

This is still a two-form sieve,

but we need only an:

$$
\boxed{
\text{upper bound}.
}
$$

There is no need to lower-bound simultaneous primes directly.

This is an important methodological asymmetry.

---

# 50. Pair-Buchstab Loss Is Also an Upper-Bound Problem

In T13:

$$
|\mathcal B_r^{pair}|
$$

is also a quantity being subtracted.

Thus it needs only an:

$$
\boxed{
\text{upper bound}.
}
$$

Therefore, throughout the cube-root descent stage:

- Buchstab shells: Upper bounds;
- Semiprime rows: Upper bounds;
- Transport overlap: Lower bounds from exact combinatorics.

The only hard classical lower sieve is moved to:

$$
\boxed{
\text{the lower cutoff }y.
}
$$

---

# 51. This Is the Main Architectural Gain

The old problem:

> Applying a dimension-2 lower sieve directly at:
> $$
> z=X^{1/3}
> $$
> as displayed above.

SRBRD-16 changes this to:

1. At:
   $$
   y\approx X^{1/5}
   $$
   Obtain lower mass;
2. Raise the cutoff using upper bounds on Buchstab losses;
3. Subtract semiprime rows at the P2 boundary;
4. Correct overlap using the transport correction.

Thus:

$$
\boxed{
\text{The hardest lower-bound work is moved to a cutoff more comfortable for the sieve.}
}
$$

This is still not a proof,

but it genuinely changes the placement of the analytic burden.

---

# 52. Relation to Weighted / Chen-Type Sieve Philosophy

One of the central ideas of external Chen-type methods is also:

> Not to require the ordinary sieve to complete all the work directly at the prime boundary;
> Instead, weighted / switching / almost-prime decompositions are added to cross the parity-sensitive region.

SRBRD-16's:

$$
\boxed{
\text{lower cutoff}
\to
\text{Buchstab descent}
\to
P_2
\to
\text{transport correction}
}
$$

is compatible with this philosophy at a high structural level.

But this document has not reproduced Chen's theorem,

nor has it thereby obtained a Goldbach proof.

---

# 53. Potential New Source

Compared with an ordinary weighted sieve, SRBRD additionally retains:

1. symmetric center coordinate；
2. exact pair least-factor shell；
3. RootRough dynamic boundary；
4. semiprime least-factor rows；
5. center-divisor transport lock；
6. $SS$ matching / flow correction。

What actually needs verification is:

> Whether these additional couplings suffice for the T13 crossing.

This has not yet been completed.

---

# 54. Analytic Provider API

It is recommended to define formally in subsequent work:

```yaml
RoughPairLower:
  cutoff: y
  output:
    L_y

PairBuchstabUpper:
  prime_r:
    y < r <= z3
  output:
    U_B_r

SemiprimeRowUpper:
  prime_r:
    r > z3
  output:
    U_row_r

InternalFlowLower:
  output:
    L_SS
```

closure：

```yaml
if:
  L_y
  - sum(U_B_r)
  - 2*sum(U_row_r)
  + L_SS
  > 0

then:
  Goldbach_success: true
```

---

# 55. Formal Theorem Queue

```yaml
SRBRD_16:
  T01: RootRough_iff_extended_lpf_gt_cutoff
  T02: pair_RootRough_iff_pair_lpf_height_gt_cutoff
  T03: exact_pair_Buchstab_identity
  T04: left_right_tie_shell_partition
  T05: cube_root_row_cofactor_forced_prime
  T06: exact_row_cofactor_formula
  T07: one_sided_semiprime_upper
  T08: row_bulk_exact_residue_sieve
  T09: row_bulk_dimension_profile
  T10: row_frontier_capacity
  T11: abstract_row_upper_provider
  T12: exact_Buchstab_Row_Flow_identity
  T13: modular_provider_lower_bound
```

---

# 56. Acceptance Gate

Before SRBRD-16 can become a formal core, it requires:

1. extended lpf with prime infinity semantics；
2. RootRough equivalence；
3. pair minimum-factor shell；
4. Buchstab shell disjointness；
5. cube-root cofactor primality theorem；
6. exact row cofactor formula；
7. row bulk / frontier split；
8. exact forbidden residues；
9. center-divisor residue collapse；
10. frontier bound；
11. one-sided upper no-go audit；
12. DHR sifting-limit statement clearly marked external；
13. no claim that DHR barrier is impossibility；
14. modular closure theorem；
15. finite audit separated from proof；
16. No Goldbach proof claim.

---

# 57. Verdict

This round can give:

$$
\boxed{
\mathrm{SRBRD\mbox{-}16\ BUCHSTAB\mbox{-}ROW\mbox{-}FLOW\ KERNEL\ PASS}.
}
$$

The most important new exact identity:

$$
\boxed{
M_{PP}
=
|\widehat{\mathcal S}_y|
-
\sum_{y<r\le z_3}
|\mathcal B_r^{pair}|
-
2\sum_{r>z_3}n_r
+
M_{SS}.
}
$$

This brings:

- coarse sieve mass；
- cutoff descent；
- semiprime contamination；
- transport rescue；

fully into a single formula for the first time.

The external sieve audit also indicates that:

$$
\boxed{
z=X^{1/3}
}
$$

is too close to the classical sifting-limit barrier for the dimension-2 lower sieve,

while:

$$
\boxed{
y\approx X^{1/5}
}
$$

is a more natural starting point for the lower sieve.

Therefore:

$$
\boxed{
\text{lower sieve at low cutoff}
+
\text{upper-bound descent}
+
\text{transport correction}
}
$$

becomes the most reasonable analytic architecture currently available.

However:

$$
\boxed{
\mathrm{UNIFORM\ CROSSING\ NOT\ YET\ PROVED}.
}
$$

and:

$$
\boxed{
\mathrm{GOLDBACH\ STILL\ OPEN}.
}
$$

---

# 58. Recommendations for the Next Round

# SRBRD-17
## Pair-Buchstab Shell / Row-Sieve Quantitative Closure

The next round should begin making T13 genuinely quantitative.

Priorities:

### A. Lower cutoff

Choose:

$$
y=X^{1/u},
\qquad
u>\beta_2,
$$

Establish an explicit:

$$
L_y.
$$

### B. Buchstab shells

For:

$$
y<r\le z_3,
$$

Establish:

$$
U_r^B
$$

and group dyadically.

### C. Semiprime rows

For:

$$
r>z_3,
$$

Use a dimension-2 upper sieve in the row bulk,

and T10's elementary bound in the frontier.

### D. Transport

Insert:

- center-divisor exact lock；
- row / block deficiency；
- selected matching lower bound。

Finally, check directly:

$$
\boxed{
L_y
-
\sum U_r^B
-
2\sum U_r^{row}
+
L_{SS}
>0.
}
$$

This will be the first round to put classical sieve constants and SRBRD transport constants into the same numerical inequality.

---

# Appendix A: Pair-Buchstab Contract

```yaml
extended_lpf:
  prime:
    infinity
  composite:
    lpf

pair_height:
  rho_m_x:
    min(
      extended_lpf(x),
      extended_lpf(2m-x)
    )

survivor_cutoff_z:
  iff:
    rho_m_x > z

shell_r:
  rho_m_x == r

identity:
  S_y:
    S_z
    disjoint_union
    shell_r_for_y_less_r_le_z
```

---

# Appendix B: Semiprime Row Cofactor Contract

```yaml
cube_cutoff:
  z3^3 >= X
  X:
    2m-3

row_r:
  r:
    prime
    r > z3

endpoint:
  x:
    r*u

range:
  r <= u <= floor(X/r)

conditions:
  RootRough_z3(r*u)
  RootRough_z3(2m-r*u)

theorem:
  u_prime:
    forced: true
```

---

# Appendix C: Row Bulk Sieve

```yaml
bulk:
  r*u <= 2m-z3^2

for_each_odd_prime_p_le_z3:
  forbidden_residues:
    - u == 0 mod p
    - u == 2m*r_inverse mod p

count:
  if_p_divides_m:
    nu_p: 1
  else:
    nu_p: 2

sieve_dimension:
  generic: 2
```

---

# Appendix D: Sieve-Depth Tradeoff

```yaml
cutoff:
  z:
    X^(1/(h+1))

RootRough_endpoint:
  max_prime_factor_count:
    h

natural_sieve_parameter:
  s:
    approximately_h_plus_1

external_dimension2_DHR:
  beta2:
    approximately_4.266

implication:
  cube_root_P2:
    s_approximately: 3
    direct_DHR_lower_positive_main_term:
      unavailable_in_standard_regime: true

  fifth_root_P4:
    s_approximately: 5
    standard_lower_sieve_regime:
      plausible: true
```

---

# Appendix E: Selected Exact Two-Cutoff Audit

| $m$ | $y$ | $z_3$ | $|\widehat{\mathcal S}_y|$ | Buchstab loss | $|\widehat{\mathcal S}_{z_3}|$ | $n_{SP}$ | $M_{SS}$ | $M_{PP}$ |
|---:|---:|---:|---:|---:|---:|---:|---:|---:|
| 1000 | 5 | 13 | 268 | 132 | 136 | 35 | 8 | 74 |
| 5000 | 7 | 22 | 954 | 430 | 524 | 152 | 34 | 254 |
| 10000 | 8 | 28 | 1908 | 954 | 954 | 291 | 90 | 462 |
| 100000 | 12 | 59 | 15584 | 9226 | 6358 | 2100 | 676 | 2834 |

---

# Appendix F: One-Sided Row No-Go

```yaml
m_1000:
  exact_nSP: 35
  one_sided_upper: 86
  resulting_PP_lower_even_with_exact_SS: -28

m_5000:
  exact_nSP: 152
  one_sided_upper: 489
  resulting_PP_lower_even_with_exact_SS: -420

m_10000:
  exact_nSP: 291
  one_sided_upper: 1022
  resulting_PP_lower_even_with_exact_SS: -1000

m_100000:
  exact_nSP: 2100
  one_sided_upper: 8856
  resulting_PP_lower_even_with_exact_SS: -10678

diagnosis:
  opposite_endpoint_RootRough_filter:
    essential: true
```

---

# Appendix G: Commit Decision

```yaml
research_round: SRBRD-16

decision:
  exact_pair_Buchstab_identity: true
  row_cofactor_prime_forced: true
  row_bulk_dimension2_sieve: true
  frontier_elementary_bound: true
  sieve_depth_tradeoff_identified: true
  modular_analytic_closure: true
  uniform_crossing: false
  goldbach_proved: false

next:
  SRBRD-17_PairBuchstabShell_RowSieve_Quantitative_Closure
```

---

# References

- C. S. Franze, “Sifting Limits for the $\Lambda^2\Lambda^-$ Sieve,” *Journal of Number Theory* 131 (2011), 1707–1725.
- H. G. Diamond and H. Halberstam, *A Higher-Dimensional Sieve Method*, Cambridge Tracts in Mathematics 177, Cambridge University Press, 2008, with computational procedures by W. F. Galway.
- T. Tao, “254A, Notes 4: Some sieve theory,” 2015.
- T. Tao, “254A, Supplement 5: The linear sieve and Chen’s theorem,” 2015.
