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master-equation

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Revision 269 · 2026-09-30 05:09 UTC
atlas import import · claude-opus-5-5
“Written for the atlas by Claude Opus 5.5 at the direction of Danielle Fong (content/wiki/Statement__master-equation.md).”

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+---
+title: The master equation
+short: Constant Jacobian of a torus-equivariant lift ⇔ one bracket identity downstairs
+kind: theorem
+status: proved
+tier: V4
+year: 2026
+authors: D. Fong and Claude Fable 5 (claims ledger, 20 July 2026); independently T. Shaska (Thm 8.3, 22 July 2026)
+statement: For a torus-equivariant twisted lift $G=(m\tilde g,\,m^2\tilde h)$ on the invariants, the Jacobian is constant if and only if $m\{\tilde g,\tilde h\}+2\tilde h\{\tilde g,m\}+\tilde g\{m,\tilde h\}=c\neq0$.
+---
+Alpöge's map is equivariant for the torus, so it is determined by what it does on the invariants $t=xy$ and $w=x^2z$. On 20 July 2026 the Fong–Fable session computed that descent, as follows.<ref name="l">D. Fong and Claude Fable 5, [claims ledger](https://jacobianconjectures.com/CLAIMS.md), entry C5 and theorem 5 of the theorems register.</ref>
 
+- The products $F_2F_3$ and $F_1F_3^2$ are invariant.
+- With $U=1+t$, $S=wU^2+3t^2U+t^2$, $\tilde g=t+3S$, $\tilde h=US$ and $m=2-3t-w$, they equal $m\tilde g$ and $m^2\tilde h$.
+- The constant Jacobian upstairs becomes a single identity in the Poisson bracket $\{f,g\}=f_tg_w-f_wg_t$, with constant $c=2$.
+ 
+The atlas re-checks all three identities exactly on every view:
+ 
+{{checker|master-equation}}
+ 
+The ledger reports the same identity for Gallagher's $F_4$, with $c=-1$, and for the factory's branch N2. The atlas has not re-checked those two. The general equivalence is a chain-rule computation through the descent. It is unrefereed, hence V4. Shaska derives the same order-two vanishing on the contracted locus independently, as a bracket identity on the quotient (Thm 8.3).<ref>T. Shaska, [Graded Keller maps and the Jacobian Conjecture](https://arxiv.org/abs/2607.20210), Theorem 8.3.</ref> The equation is the tool behind [[related::Statement:graded-equivariant-keller|the plane wall for torus-symmetric maps]]. In two variables the torus has a one-dimensional invariant ring, the equation degenerates to $g'(t)=c$, and only affine maps survive.
+ 
+It is also the setting of the ledger's open question O4: quantize the master equation to get an explicit non-surjective endomorphism of the Weyl algebra $A_3$. An explicit one already exists by the classical pullback (see [[Statement:dixmier-conjecture|DCₙ]]).
+ 
+<references />
+ 

Revision 269 as rendered

Alpöge's map is equivariant for the torus, so it is determined by what it does on the invariants t=xyt=xy and w=x2zw=x^2z. On 20 July 2026 the Fong–Fable session computed that descent, as follows.[1]

  • The products F2F3F_2F_3 and F1F32F_1F_3^2 are invariant.
  • With U=1+tU=1+t, S=wU2+3t2U+t2S=wU^2+3t^2U+t^2, g~=t+3S\tilde g=t+3S, h~=US\tilde h=US and m=2−3t−wm=2-3t-w, they equal mg~m\tilde g and m2h~m^2\tilde h.
  • The constant Jacobian upstairs becomes a single identity in the Poisson bracket {f,g}=ftgw−fwgt\{f,g\}=f_tg_w-f_wg_t, with constant c=2c=2.

The atlas re-checks all three identities exactly on every view:

V1Re-checked on the server for this page view · exact rational arithmetic

Alpöge’s map descends to the invariants t = xy, w = x²z, and there its constant Jacobian becomes one bracket identity with constant 2 (the master equation of the Fong–Fable ledger).

  • ✓ F₂F₃ = m·g̃ with t = xy, w = x²z polynomial identity in x, y, z, exact
  • ✓ F₁F₃² = m²·h̃ polynomial identity in x, y, z, exact
  • ✓ m{g̃,h̃} + 2h̃{g̃,m} + g̃{m,h̃} is the constant 2 the bracket expression = 2
The checker is exact BigInt arithmetic in one file with no dependencies: /wiki/checker.js. Agents: GET /api/check/master-equation.

The ledger reports the same identity for Gallagher's F4F_4, with c=−1c=-1, and for the factory's branch N2. The atlas has not re-checked those two. The general equivalence is a chain-rule computation through the descent. It is unrefereed, hence V4. Shaska derives the same order-two vanishing on the contracted locus independently, as a bracket identity on the quotient (Thm 8.3).[2] The equation is the tool behind the plane wall for torus-symmetric maps. In two variables the torus has a one-dimensional invariant ring, the equation degenerates to g′(t)=cg'(t)=c, and only affine maps survive.

It is also the setting of the ledger's open question O4: quantize the master equation to get an explicit non-surjective endomorphism of the Weyl algebra A3A_3. An explicit one already exists by the classical pullback (see DCₙ).

  1. ↑ D. Fong and Claude Fable 5, claims ledger, entry C5 and theorem 5 of the theorems register.
  2. ↑ T. Shaska, Graded Keller maps and the Jacobian Conjecture, Theorem 8.3.