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

# ACTM Round 31
## Two-Observable Kummer Orbit, Generic Fiber Escape, and Quadratic Joint-Degree Growth
### Two-Observable Kummer Orbits, Escape from Exceptional Fibers, and Quadratic Joint-Degree Growth

**Research programme:** Algebraic Combinatorial Transcendence Methodology (ACTM)  
**Authors:** Neo.K; Aletheia (GPT-5.6 Sol)  
**Institution:** EveMissLab / 一言諾科技有限公司  
**Date:** 2026-10-03  
**Version:** Round 31 / v0.1  
**Document type:** Formal research note / two-observable Kummer-fiber round  
**Status statement:** This round does not claim the impossibility of real BADT$_2$, nor that an individual interpolation slope has cubic algebraic degree. It proves that, for fixed interpolation size $M$, the first- and second-layer extremal interpolation slopes, considered as a pair of observables, have joint algebraic degree growing at least as $Q^2$. The core mechanism is that the combined BADT Kummer rank is $4$, the two-observable map has generic fiber dimension $2$, and the BADT rational-flattening path hits exceptional higher-dimensional fibers only finitely many times.

---

## Abstract

For the first-layer interpolation slope:

$$
\alpha_Q
=
R_M(A_Q,B_Q,C_Q)
$$

Round 30 proves:

$$
[\mathbb Q(\alpha_Q):\mathbb Q]
\gg_M Q.
$$

where:

$$
A_Q=A^{1/Q},
\quad
B_Q=B^{1/Q},
\quad
C_Q=C^{1/Q}.
$$

The reasons are:

- Kummer rank $3$ supplies:
  $$
  \Omega(Q^3)
  $$
  twists;
- a scalar rational observable has generic value-fiber dimension $2$;
- Within:
  $$
  \mu_Q^3
  $$
  a bounded-degree fiber has:
  $$
  O_M(Q^2)
  $$
  points.

Round 31, for the first time, genuinely uses the second BADT layer as an additional independent observable.

Let:

$$
D=e^{s^4\lambda},
$$

$$
D_Q=D^{1/Q},
$$

and define the second-layer interpolation slope:

$$
\beta_Q
=
R_M(A_Q,C_Q,D_Q).
$$

Define the pair-observable map:

$$
\boxed{
\Phi_M:
(\mathbb G_m)^4
\dashrightarrow
\mathbb A^2
}
$$

by:

$$
\boxed{
\Phi_M(X,Y,Z,W)
=
\left(
R_M(X,Y,Z),
R_M(X,Z,W)
\right).
}
$$

The core theorem of this round:

## Two-Observable Joint-Degree Theorem

For fixed:

$$
M\ge2,
$$

there exist:

$$
c_M>0,
$$

and:

$$
Q_0(M,A,B,C,D),
$$

such that for all:

$$
Q\ge Q_0,
$$

we have:

$$
\boxed{
[
\mathbb Q(\alpha_Q,\beta_Q)
:
\mathbb Q
]
\ge
c_MQ^2.
}
$$

Thus the second layer strictly improves the single-layer linear element-degree lower bound:

$$
\Omega(Q)
$$

to the pair-level bound:

$$
\boxed{
\Omega(Q^2).
}
$$

This is the first time the second BADT layer provides a rigorous gain in the arithmetic complexity of interpolation elements.

---

# 1. Universal interpolation rational function

Fix:

$$
M\ge2,
$$

$$
L=M^2.
$$

For formal variables:

$$
X,Y,Z,
$$

let:

$$
R_M(X,Y,Z)
$$

be the universal extremal interpolation derivative defined in Rounds 29–30:

$$
R_M(X,Y,Z)
=
H_{X,Y,Z}'(1),
$$

where:

$$
H_{X,Y,Z}
$$

interpolates:

$$
X^aY^b
\mapsto
Y^aZ^b
$$

for:

$$
0\le a,b<M.
$$

Round 30 has proved:

1. $R_M$ is nonconstant;
2. $R_M$ genuinely depends on $Y$;
3. $R_M$ genuinely depends on $Z$;
4. $\deg_ZR_M=M-1>0$;
5. its toric translation stabilizer is finite.

This round needs only items 2 and 3 to establish two-observable independence.

---

# 2. Two observables

Define:

$$
R_1
=
R_M(X,Y,Z),
$$

$$
R_2
=
R_M(X,Z,W).
$$

Note that:

$$
R_1
$$

does not depend on:

$$
W,
$$

while:

$$
R_2
$$

does not depend on:

$$
Y.
$$

and:

$$
\frac{\partial R_1}{\partial Y}
\not\equiv0,
$$

$$
\frac{\partial R_2}{\partial W}
\not\equiv0.
$$

---

# 3. Jacobian minor

Consider:

$$
\Phi_M
=
(R_1,R_2).
$$

The Jacobian with respect to the variables:

$$
Y,W
$$

has the $2\times2$ minor:

$$
\det
\begin{pmatrix}
\partial_YR_1 & \partial_WR_1\\
\partial_YR_2 & \partial_WR_2
\end{pmatrix}.
$$

Since:

$$
\partial_WR_1=0,
$$

$$
\partial_YR_2=0,
$$

we have:

$$
\boxed{
J_{YW}
=
(\partial_YR_1)
(\partial_WR_2)
\not\equiv0.
}
$$

Thus:

$$
\boxed{
\operatorname{rank}d\Phi_M=2
}
$$

generically.

---

# 4. Algebraic independence

By the generic Jacobian rank $2$:

$$
\boxed{
R_1,
\quad
R_2
}
$$

in:

$$
\mathbb Q(X,Y,Z,W)
$$

are algebraically independent.

Equivalently:

$$
\Phi_M
$$

is a dominant rational map:

$$
(\mathbb G_m)^4
\dashrightarrow
\mathbb A^2.
$$

Thus the generic fiber dimension is:

$$
\boxed{
4-2=2.
}
$$

---

# 5. Domain of regular definition

Let:

$$
U_M
\subset
(\mathbb G_m)^4
$$

be the maximal open subset on which:

$$
R_1,
R_2
$$

both functions are regular.

For the positive-real BADT point:

$$
p_Q
=
(A_Q,B_Q,C_Q,D_Q),
$$

all first- and second-layer interpolation nodes are distinct.

A node collision, for example:

$$
A_Q^aB_Q^b
=
A_Q^{a'}B_Q^{b'}
$$

would give:

$$
(a-a')+(b-b')s=0,
$$

which is excluded by the irrationality of $s$.

The same reasoning applies to the second layer.

Thus:

$$
\boxed{
p_Q\in U_M
}
$$

for every:

$$
Q\ge1.
$$

---

# 6. Generic-fiber open set

The dominant rational map:

$$
\Phi_M
$$

restricts to:

$$
U_M
\to
\mathbb A^2.
$$

By the generic-fiber dimension theorem / generic flatness, there exists a nonempty Zariski-open subset:

$$
\Omega_M
\subset
\mathbb A^2
$$

such that for:

$$
y\in\Omega_M,
$$

the fiber:

$$
\Phi_M^{-1}(y)
$$

has dimension:

$$
\boxed{
2.
}
$$

Let the exceptional target locus be:

$$
E_M
=
\mathbb A^2
\setminus
\Omega_M.
$$

Then:

$$
\boxed{
E_M
}
$$

is a proper algebraic subset.

---

# 7. Flattening path

Define the analytic one-parameter BADT path:

$$
p(t)
=
\left(
e^{\lambda t},
e^{s\lambda t},
e^{s^2\lambda t},
e^{s^4\lambda t}
\right).
$$

Then:

$$
p_Q=p(1/Q).
$$

---

# 8. Zariski density of the BADT path

If a nonzero Laurent polynomial:

$$
F
=
\sum_m
c_m
X_0^{m_0}
X_1^{m_1}
X_2^{m_2}
X_4^{m_4}
$$

vanishes identically on:

$$
p(t),
$$

then:

$$
0
=
F(p(t))
=
\sum_m
c_m
e^{
\lambda t
(
m_0+m_1s+m_2s^2+m_4s^4
)
}.
$$

Since:

$$
1,s,s^2,s^4
$$

are Q-linearly independent, distinct exponent vectors:

$$
m
$$

give distinct real frequencies.

Distinct exponentials are linearly independent.

Thus:

$$
c_m=0
$$

for all:

$$
m.
$$

a contradiction.

Therefore:

$$
\boxed{
\overline{
\{p(t):t\in\mathbb C\}
}^{\mathrm{Zar}}
=
(\mathbb G_m)^4.
}
$$

Under the local analytic interpretation, any small interval of nonzero $t$ already suffices for Zariski density.

---

# 9. Exceptional fibers cannot recur infinitely along $1/Q$

Suppose:

$$
\Phi_M(p_Q)
\in
E_M
$$

for infinitely many:

$$
Q.
$$

Since:

$$
E_M
$$

is proper, there exists a nonzero polynomial:

$$
H(U,V)
$$

vanishing on:

$$
E_M.
$$

Then:

$$
h(t)
=
H(
R_1(p(t)),
R_2(p(t))
)
$$

is analytic in a punctured neighborhood of:

$$
0
$$

and the interpolation asymptotics make its singularity at:

$$
t=0
$$

removable.

If:

$$
h(1/Q)=0
$$

infinitely often, with accumulation at:

$$
0,
$$

the identity theorem gives:

$$
h(t)\equiv0.
$$

Thus the rational function:

$$
H(R_1,R_2)
$$

vanishes on the Zariski-dense BADT path.

Hence:

$$
H(R_1,R_2)\equiv0.
$$

But:

$$
R_1,R_2
$$

are algebraically independent.

A contradiction.

Therefore:

## Exceptional-Fiber Escape Lemma

$$
\boxed{
\Phi_M(p_Q)\in\Omega_M
}
$$

for all sufficiently large:

$$
Q.
$$

Thus:

$$
\boxed{
\dim
\Phi_M^{-1}
(
\alpha_Q,\beta_Q
)
=
2
}
$$

eventually.

---

# 10. Uniform fiber degree

Let:

$$
\Gamma_M
$$

be the projective / affine closure of the graph of:

$$
\Phi_M
$$

as displayed above.

Since:

$$
M
$$

is fixed:

$$
\Gamma_M
$$

has degree:

$$
\Delta_M
$$

a fixed finite constant.

For:

$$
y\in\Omega_M,
$$

the fiber:

$$
\Gamma_{M,y}
$$

is the intersection of the graph with a target-coordinate linear slice.

By Bézout / degree monotonicity:

$$
\boxed{
\deg
\Gamma_{M,y}
\le
\Delta_M.
}
$$

Projecting the fiber back to the source torus and taking its closure gives a degree controlled by another constant depending only on $M$.

Thus there exists:

$$
\boxed{
D_M^{\mathrm{fib}}
}
$$

such that every good fiber has:

- dimension $2$;
- degree at most:
  $$
  D_M^{\mathrm{fib}}.
  $$

---

# 11. Algebraic-grid point bound

Use the standard degree–dimension Cartesian-grid bound:

If:

$$
V
\subset
\mathbb A^n
$$

is an algebraic set of dimension:

$$
d
$$

and degree:

$$
\Delta
$$

as displayed above,

and:

$$
S
$$

is a finite subset of the ground field,

then:

$$
\boxed{
|V\cap S^n|
\le
C(n,\Delta)|S|^d.
}
$$

For fixed:

$$
n=4,
$$

and bounded:

$$
\Delta,
$$

one need only write:

$$
O_{\Delta}( |S|^d ).
$$

This bound can be proved by Bézout + induction / variety Schwartz–Zippel.

Take:

$$
S=\mu_Q,
$$

$$
|S|=Q.
$$

Thus a good two-dimensional fiber has at most:

$$
\boxed{
C_MQ^2.
}
$$

---

# 12. Translation to collision fibers

Define:

$$
y_Q
=
(\alpha_Q,\beta_Q)
=
\Phi_M(p_Q).
$$

The pair-value collision set is:

$$
\mathcal C_Q
=
\{
\xi\in\mu_Q^4:
\Phi_M(\xi p_Q)
=
\Phi_M(p_Q)
\}.
$$

The diagonal multiplication:

$$
\xi
\mapsto
\xi p_Q
$$

is a torus automorphism.

Thus:

$$
\mathcal C_Q
$$

is the intersection of a good fiber with a translated torsion grid.

Degree / dimension are unchanged.

Therefore:

$$
\boxed{
|\mathcal C_Q|
\le
C_MQ^2
}
$$

for sufficiently large:

$$
Q.
$$

---

# 13. Combined Kummer rank

Let:

$$
K_4
=
\mathbb Q(A,B,C,D).
$$

Round 29 proves:

$$
\langle A,B,C,D\rangle
$$

is a torsion-free multiplicative subgroup of rank $4$.

The Perucca–Sgobba theorem gives a fixed:

$$
C_{\mathrm{Kum}}
$$

such that:

$$
\boxed{
[
K_4(
\zeta_Q,
A_Q,B_Q,C_Q,D_Q
)
:
K_4(\zeta_Q)
]
\ge
\frac{
Q^4
}{
C_{\mathrm{Kum}}
}.
}
$$

---

# 14. Kummer Galois twists

Let:

$$
L_Q
=
K_4(
\zeta_Q,
A_Q,B_Q,C_Q,D_Q
).
$$

The extension:

$$
L_Q/K_4(\zeta_Q)
$$

is a Kummer Galois extension.

Its Galois group:

$$
G_Q
$$

injects into:

$$
\mu_Q^4
$$

by:

$$
(A_Q,B_Q,C_Q,D_Q)
\mapsto
(
\xi_1A_Q,
\xi_2B_Q,
\xi_3C_Q,
\xi_4D_Q
).
$$

and:

$$
\boxed{
|G_Q|
\ge
Q^4/C_{\mathrm{Kum}}.
}
$$

---

# 15. Stabilizer of the observable pair

A Galois automorphism:

$$
\sigma_\xi
$$

fixes:

$$
(\alpha_Q,\beta_Q)
$$

if and only if:

$$
\Phi_M(\xi p_Q)
=
\Phi_M(p_Q).
$$

Thus:

$$
\operatorname{Stab}_{G_Q}
(\alpha_Q,\beta_Q)
\subset
\mathcal C_Q.
$$

Therefore:

$$
\boxed{
|
\operatorname{Stab}_{G_Q}
(\alpha_Q,\beta_Q)
|
\le
C_MQ^2.
}
$$

---

# 16. Pair orbit size

Orbit–stabilizer gives:

$$
|
G_Q\cdot
(\alpha_Q,\beta_Q)
|
=
\frac{
|G_Q|
}{
|
\operatorname{Stab}_{G_Q}
(\alpha_Q,\beta_Q)
|
}.
$$

Thus:

$$
\boxed{
|
G_Q\cdot
(\alpha_Q,\beta_Q)
|
\ge
\frac{
Q^4/C_{\mathrm{Kum}}
}{
C_MQ^2
}
=
c_MQ^2.
}
$$

---

# 17. Relative joint field degree

The Galois orbit size is:

$$
\boxed{
[
K_4(
\zeta_Q,
\alpha_Q,\beta_Q
)
:
K_4(\zeta_Q)
]
}
$$

so:

$$
\boxed{
[
K_4(
\zeta_Q,
\alpha_Q,\beta_Q
)
:
K_4(\zeta_Q)
]
\ge
c_MQ^2.
}
$$

---

# 18. Absolute joint degree

Let:

$$
E_Q
=
\mathbb Q(\alpha_Q,\beta_Q).
$$

Then:

$$
K_4(\zeta_Q,E_Q)
=
K_4(\zeta_Q,\alpha_Q,\beta_Q).
$$

The general field-compositum inequality gives:

$$
[
K_4(\zeta_Q,E_Q)
:
K_4(\zeta_Q)
]
\le
[E_Q:\mathbb Q].
$$

Therefore:

## Two-Observable Joint-Degree Theorem

$$
\boxed{
[
\mathbb Q(\alpha_Q,\beta_Q)
:
\mathbb Q
]
\ge
c_MQ^2.
}
$$

for sufficiently large:

$$
Q.
$$

---

# 19. Why this is genuinely a second-layer gain

The first layer alone:

$$
\alpha_Q
$$

comes from a Kummer torus of rank $3$ + one scalar observable:

$$
3-1=2
$$

fiber dimensions,

giving:

$$
\boxed{
\deg\alpha_Q
\gg Q.
}
$$

With the second layer:

$$
(\alpha_Q,\beta_Q)
$$

comes from a Kummer torus of rank $4$ + two independent observables:

$$
4-2=2
$$

fiber dimensions,

giving:

$$
\boxed{
\deg(\alpha_Q,\beta_Q)
\gg Q^2.
}
$$

Thus:

$$
\boxed{
\text{second layer contributes one full additional power of }Q
}
$$

in rigorously visible element-level arithmetic complexity.

---

# 20. Fiber-dimension accounting principle

This round suggests a general pattern:

If:

- the multiplicative Kummer rank is:
  $$
  r;
  $$
- the number of algebraically independent scalar observables is:
  $$
  k;
  $$
- good fibers are:
  $$
  r-k
  $$
  dimensional;

then a bounded-degree Cartesian-grid argument naturally gives:

$$
\boxed{
\text{joint observable degree}
\gtrsim
Q^k.
}
$$

provided the flattening path eventually avoids exceptional fibers.

Round 30:

$$
(r,k)=(3,1)
\Rightarrow
Q.
$$

Round 31:

$$
(r,k)=(4,2)
\Rightarrow
Q^2.
$$

---

# 21. Why exceptional fibers mattered

If the pair-value fiber dimension jumps to:

$$
3,
$$

torsion-grid collisions can return to:

$$
O(Q^3),
$$

leaving only:

$$
\Omega(Q)
$$

as the joint orbit size.

Thus one cannot rely solely on the generic-dimension heuristic from algebraic independence.

The genuine additional result of this round is:

$$
\boxed{
\text{BADT flattening path eventually escapes the exceptional fiber locus}.
}
$$

This makes the:

$$
Q^2
$$

bound a theorem, not a generic heuristic.

---

# 22. Why the escape argument works unusually well here

The key is that:

$$
p_Q=p(1/Q)
$$

is not an arbitrary sequence.

It comes from:

$$
p(t)
=
(
e^{\lambda t},
e^{s\lambda t},
e^{s^2\lambda t},
e^{s^4\lambda t}
).
$$

Since:

$$
1,s,s^2,s^4
$$

are Q-linearly independent, this analytic curve is Zariski dense.

Also:

$$
1/Q
$$

accumulates at:

$$
0.
$$

Thus, if any fixed algebraic exceptional condition is hit for infinitely many $Q$, the analytic identity theorem turns it into an identity along the whole exponential curve, which Zariski density then excludes.

---

# 23. Relation to torsion-point counting literature

Schefer 2025 gives general sharp growth upper bounds for torsion points on fixed torus subvarieties and power savings away from maximal torsion-coset behavior.

The method of Round 31 is different:

- fibers vary with:
  $$
  Q
  $$
  the parameter displayed above;
- no power saving is needed;
- only the good fiber dimension:
  $$
  2
  $$
  and a uniform degree are needed;
- then use the generic algebraic-grid:
  $$
  O(Q^2)
  $$
  count.

Thus it avoids the varying-fiber torsion-coset obstacle of Round 30.

If one wishes in future to improve:

$$
Q^2
$$

further, a finer theory of torsion-coset sparsity is still needed.

---

# 24. Pair approximation remains nonexact

Round 29 has proved:

$$
\boxed{
|\beta_Q-\alpha_Q^2|
\asymp
Q^{-(M^2-1)}.
}
$$

Thus, even though:

$$
(\alpha_Q,\beta_Q)
$$

has joint degree at least:

$$
Q^2,
$$

they are still not exact points of the parabola:

$$
V=U^2.
$$

Therefore:

$$
\boxed{
\text{joint degree growth alone does not close BADT}.
}
$$

---

# 25. Height status

The interpolation-height argument of Round 28 also applies to the second layer:

$$
h(\alpha_Q)=O_M(1),
$$

$$
h(\beta_Q)=O_M(1).
$$

Thus:

$$
\boxed{
h(\alpha_Q,\beta_Q)=O_M(1)
}
$$

for fixed:

$$
M.
$$

We therefore now have:

$$
\boxed{
\text{bounded height}
+
\text{joint degree }\Omega(Q^2)
+
\text{distance to parabola }Q^{-(M^2-1)}.
}
$$

these three quantities simultaneously.

---

# 26. A new arithmetic-geometric interface

Define the defect:

$$
\delta_Q
=
\beta_Q-\alpha_Q^2.
$$

Then:

$$
\boxed{
|\delta_Q|
\asymp
Q^{-(M^2-1)}.
}
$$

and:

$$
h(\delta_Q)=O_M(1).
$$

But:

$$
\delta_Q
$$

has currently unknown individual algebraic degree.

The joint degree of the pair:

$$
\Omega(Q^2)
$$

does not automatically give:

$$
\deg\delta_Q
\gg Q^2.
$$

because subtraction / squaring may greatly enlarge the stabilizer.

Thus the new natural observable is:

$$
\boxed{
\Psi_M
=
R_M(X,Z,W)
-
R_M(X,Y,Z)^2.
}
$$

Its Kummer orbit / fiber geometry can be studied separately.

---

# 27. Defect-Degree Problem

A candidate question for Round 32:

**Defect-Degree Problem (DDP)**

For:

$$
\delta_Q
=
\Psi_M(p_Q),
$$

can one prove:

$$
\boxed{
[\mathbb Q(\delta_Q):\mathbb Q]
\gg
Q^\theta
}
$$

for some:

$$
\theta>1?
$$

The generic fiber of a scalar observable of rank $4$ gives only:

$$
\theta=1.
$$

To exceed $1$, one must use:

- the special structure of $\Psi_M$;
- the pair's joint degree;
- the relation between the pair fiber and the defect fiber;
- torsion-coset sparsity.

---

# 28. Double-scaling alternative

Another Round 32 route is not to improve the defect degree, but to let the interpolation order:

$$
r=M^2-1
$$

grow with:

$$
Q
$$

the parameter displayed above.

Since:

$$
|\delta_Q|
\sim
Q^{-r},
$$

if one can control:

- height growth in $M$;
- upper degree growth in $Q,M$;
- leading constants;

then a Liouville / norm lower bound may collide with high-order analytic approximation.

This requires moving from the fixed-$M$ regime into:

$$
\boxed{
M=M(Q)
}
$$

double scaling.

---

# 29. Round 31 Assessment

**PASS — The two BADT interpolation slopes form algebraically independent observables; the flattening path eventually avoids exceptional higher-dimensional fibers; combined rank-4 Kummer theory yields quadratic joint-degree growth**

This round completes:

1. Definition of:
   $$
   \Phi_M(X,Y,Z,W)
   =
   (
   R_M(X,Y,Z),
   R_M(X,Z,W)
   ).
   $$

2. Using the genuine variable dependence of Round 30 to establish a nonzero Jacobian minor.

3. A proof that the two observables are algebraically independent.

4. The generic fiber dimension:
   $$
   2.
   $$

5. Definition of the exceptional higher-dimensional target locus.

6. A proof that the one-parameter BADT flattening path is Zariski dense in:
   $$
   (\mathbb G_m)^4.
   $$

7. Using analytic accumulation at:
   $$
   t=0
   $$
   to exclude infinitely recurring exceptional fibers.

8. The exact fiber dimension for sufficiently large $Q$:
   $$
   2.
   $$

9. Construction of a uniform fiber-degree bound.

10. Use of the algebraic-grid / variety Schwartz–Zippel bound:
    $$
    O_M(Q^2).
    $$

11. Application of the Perucca–Sgobba Kummer lower bound of rank $4$:
    $$
    \Omega(Q^4).
    $$

12. Using orbit–stabilizer to obtain:
    $$
    \boxed{
    [
    K_4(\zeta_Q,\alpha_Q,\beta_Q)
    :
    K_4(\zeta_Q)
    ]
    \gg_M
    Q^2.
    }
    $$

13. The resulting absolute bound:
    $$
    \boxed{
    [
    \mathbb Q(\alpha_Q,\beta_Q)
    :
    \mathbb Q
    ]
    \gg_M
    Q^2.
    }
    $$

14. Construction of the fiber-dimension accounting principle for Kummer rank / observable count.

15. Identification of the first rigorous element-level gain from the second layer:
    $$
    Q\to Q^2.
    $$

16. Pinpointing the next defect-degree / double-scaling problem.

---

# 30. The Formal Entry Point for Round 32

It is proposed that Round 32 assess two lines simultaneously, ultimately retaining the stronger one.

## R32-A: The Defect Observable's Kummer Orbit

Study:

$$
\Psi_M(X,Y,Z,W)
=
R_M(X,Z,W)
-
R_M(X,Y,Z)^2.
$$

First analyse:

- the toric stabilizer;
- the generic fiber;
- special factorization;
- the torsion-grid collision count.

If defect fibers are unusually sparse, one can improve:

$$
\deg\delta_Q.
$$

---

## R32-B: Joint-to-Defect Descent

It is known that:

$$
\deg(\alpha_Q,\beta_Q)\gg Q^2.
$$

Study the extension tower:

$$
\mathbb Q(\delta_Q)
\subset
\mathbb Q(\alpha_Q,\beta_Q),
$$

where:

$$
\beta_Q
=
\alpha_Q^2+\delta_Q.
$$

Thus:

$$
\mathbb Q(\alpha_Q,\beta_Q)
=
\mathbb Q(\alpha_Q,\delta_Q).
$$

If one can upper-bound:

$$
[
\mathbb Q(\alpha_Q,\delta_Q)
:
\mathbb Q(\delta_Q)
]
$$

by:

$$
O(Q^\rho)
$$

with:

$$
\rho<2,
$$

then part of the joint degree can be passed to the defect.

---

## R32-C: Double Scaling

Let:

$$
M=M(Q)\to\infty.
$$

Balance:

$$
|\delta_Q|
\approx
Q^{-M^2}
$$

against algebraic lower bounds depending on:

- degree;
- height;
- $M$.

The objective is to find whether there is a growth window:

$$
M(Q)
$$

in which analytic decay overwhelms arithmetic complexity.

---

# 31. One-Sentence Conclusion

> **Round 31 proves that the second layer genuinely provides a quantifiable element-level arithmetic gain for the first time. The universal interpolation slopes $R_M(X,Y,Z)$ and $R_M(X,Z,W)$ are algebraically independent, so the pair map has two-dimensional generic fibers; the BADT rational-flattening path is also Zariski dense because $1,s,s^2,s^4$ are linearly independent, so it can hit higher-dimensional exceptional fibers only finitely many times. For large $Q$, the pair-collision fiber is a bounded-degree two-dimensional variety, and on $\mu_Q^4$ it has only $O(Q^2)$ points, while the combined Kummer orbit has $\Omega(Q^4)$ twists. Thus the joint algebraic degree of $(\alpha_Q,\beta_Q)$ is at least $\Omega(Q^2)$.**

The current state:

$$
\boxed{
h(\alpha_Q),h(\beta_Q)=O_M(1),
}
$$

$$
\boxed{
\deg(\alpha_Q,\beta_Q)\gg_M Q^2,
}
$$

$$
\boxed{
|\beta_Q-\alpha_Q^2|
\asymp
Q^{-(M^2-1)}.
}
$$

The genuine question for the next round is whether this $Q^2$ joint complexity can be passed to the tiny defect, or whether allowing $M$ to grow with $Q$ can produce a collision with algebraic lower bounds.

---

# References

1. Antonella Perucca and Pietro Sgobba, **Kummer theory for number fields and the reductions of algebraic numbers**, *International Journal of Number Theory* 15 (2019), 1617–1633.  
   DOI: 10.1142/S179304211950091X.  
   Their main theorem states that for a torsion-free rank-$r$ subgroup $G\subset K^\times$,
   $$
   \frac{
   n^r
   }{
   [K(\zeta_n,\sqrt[n]{G}):K(\zeta_n)]
   }
   $$
   is bounded independently of $n$.

2. Antonella Perucca, **The degree of non-Galois Kummer extensions of number fields**, *Rivista di Matematica della Università di Parma* 11 (2020), 301–313.

3. Standard generic-fiber dimension theorem and generic flatness for dominant morphisms of algebraic varieties.

4. Standard Bézout degree inequalities and degree–dimension Cartesian-grid bounds / variety Schwartz–Zippel estimates.

5. Gerold Schefer, **Counting torsion points on subvarieties of the algebraic torus**, *Acta Arithmetica* 218 (2025), 297–336.  
   DOI: 10.4064/aa221025-14-1.  
   Provides sharp torsion-point growth bounds for fixed torus subvarieties and power-saving bounds away from maximal torsion-coset behavior.

---

**End of ACTM Round 31**
