ExactW3Center
Abstract
An algebraic critical-root lift in original parent coordinates
criticalPolynomial is the degree-67 real polynomial with the descending FC integer coefficient list. It has a unique real root b3 in the open interval (12758053/100000000,12758054/100000000). criticalRoot denotes this root, not a rounded coordinate. The derivative is strictly negative throughout the closed isolating interval. Opposite endpoint signs and the intermediate value theorem give existence; strict decrease gives uniqueness.
A narrower exact enclosure is 127580539798972/1000000000000000 < b3 < 127580539798973/1000000000000000. Polynomial bounds are proved by Horner recurrence. At each recurrence the lower and upper endpoints bound both products with the interval endpoints; induction preserves the enclosure. All coefficient arithmetic and endpoint comparisons use exact integers and rationals.
determinantalLiftDenominator and determinantalLiftNumerator are explicit integer coefficient arrays defining a candidate algebraic lift. Set r(b)=-determinantalLiftNumerator(b)/determinantalLiftDenominator(b), and liftedCoordinates(b)=(r(b)/b,b). exactW3 is chartWorld(liftedCoordinates(b3)), expressed in ordinary cubic coefficients. Identifying these arrays with the reduced fixed-determinant polynomials requires the separate correspondence stated below.
The denominator is positive on the narrower interval, and the quotient satisfies 9005/10000 <= r(b3) <= 9006/10000. Also 12758/100000 <= b3 <= 12759/100000. These are proved bounds, so SourceCertificate imposes no additional assumption in exactW3_parent. The genuine independent coordinates are (t,b) with t=r/b; no bound t<1 is used.
The chart reconstructs one whole gain polynomial and drift from the literal parent history. Consequently this algebraic lift is an OriginalParent. chartWorld, the original eight-coordinate chartSource, and chartRead=(originalResponse.first,futureRead at the empty common word) are analytic at its lifted coordinates. Every OriginalParent with the same r and b equals this world, including lower degree polynomials and zero samples permitted by the original model.
At this same exact lifted coordinate, exactW3_parent applies the actual local source inverse. It supplies an open partial homeomorphism whose forward map is chartRead, a positive-radius convex read ball with compact closure inside the inverse and analytic domains, a finite derivative bound and Lipschitz estimate for the complete eight-coordinate source vector, and the center-world membership and pairwise estimate for all worlds in that local neighborhood. This is a local consequence of the compiled actual Jacobian and inverse theorem.
The regular whole-world correspondence identifies the reconstructed world with the Ck/D lift at these same source coordinates. Identification of the explicit coefficient arrays with the fixed determinant definition remains a separate algebraic obligation. Thus this construction alone does not identify the world with a determinantal critical center. The parent and analyticity conclusions here alone supply neither the remote branch nor exhaustion of the original preimage.
The fixed-minor bridge encodes the literal 28 rows in columns r^28,…,1. Retaining the first 27 columns and appending the r or constant column gives fixedMinorR and fixedMinorC; fixed_minor_linear_relation proves the necessary relation z det(fixedMinorR)+det(fixedMinorC)=0 from the row-wise common-root equation. This is the exact no-specialization implication used by the source’s Lemma 4.3, including leading-coefficient drops. The source-specific expansion of E0 and E1, the 1080 determinant comparisons, and the equality of these determinants with the stored coefficient arrays remain open, so this bridge does not yet identify the selected criticalRoot lift with the source-defined W3.
Theorem 1.1 (exact degree-67 critical root).
Lean statement: D5/S3/Observer/CubicGain/ExactW3Center.critical_root_exists
Proof. Machine-checked in Lean as D5/S3/Observer/CubicGain/ExactW3Center.critical_root_exists (✓ std3). ∎
Source. Repository-derived.
Commentary.
criticalPolynomial has degree 67. There exists a real b strictly between rootLo=12758053/100000000 and rootHi=12758054/100000000 with criticalPolynomial.eval(b)=0.
Theorem 1.2 (selected root specification).
Lean statement: D5/S3/Observer/CubicGain/ExactW3Center.criticalRoot_spec
Proof. Machine-checked in Lean as D5/S3/Observer/CubicGain/ExactW3Center.criticalRoot_spec (✓ std3). ∎
Source. Repository-derived.
Commentary.
The selected real criticalRoot satisfies rootLo<criticalRoot, criticalRoot<rootHi and criticalPolynomial.eval(criticalRoot)=0. No parameter or hypothesis is required.
Theorem 1.3 (parent lift from rational strip conditions).
Lean statement: D5/S3/Observer/CubicGain/ExactW3Center.exactW3_parent_of_source_certificate
Proof. Machine-checked in Lean as D5/S3/Observer/CubicGain/ExactW3Center.exactW3_parent_of_source_certificate (✓ std3). ∎
Source. Repository-derived.
Commentary.
For h:SourceCertificate, OriginalParent exactW3 and AnalyticAt Real chartRead (liftedCoordinates criticalRoot) hold. SourceCertificate is the conjunction of the two rational r bounds, the two rational b bounds and nonvanishing of the determinantalLiftDenominator at criticalRoot.
Theorem 1.4 (unconditional algebraic parent lift).
Lean statement: D5/S3/Observer/CubicGain/ExactW3Center.exactW3_parent
Proof. Machine-checked in Lean as D5/S3/Observer/CubicGain/ExactW3Center.exactW3_parent (✓ std3). ∎
Source. Repository-derived.
Commentary.
With no hypotheses, SourceCertificate and OriginalParent exactW3 hold, and chartWorld, chartSource and chartRead are analytic at liftedCoordinates criticalRoot. For every real b in the original open isolating interval, criticalPolynomial.eval(b)=0 implies b=criticalRoot. For every W:OriginalWorld, OriginalParent W, W.first=liftedR criticalRoot and W.second.first=criticalRoot imply W=exactW3. The same theorem returns the compiled actual local source inverse centered at liftedCoordinates criticalRoot, including its analytic inverse neighborhood, complete source-vector Lipschitz estimate, center membership, and all pairwise local-world bounds. It does not prove that the explicit numerator and denominator arrays are the fixed 28-row minors from Definition 4.1, so the source identity of this candidate lift remains open.
Theorem 1.5 (literal fixed-minor necessary relation).
Lean statement: D5/S3/Observer/CubicGain/ExactW3Center.fixed_minor_linear_relation
Proof. Machine-checked in Lean as D5/S3/Observer/CubicGain/ExactW3Center.fixed_minor_linear_relation (✓ std3). ∎
Source. Repository-derived.
Commentary.
For a 28-by-29 coefficient matrix whose columns are ordered r^28,…,1, the row-wise common-root equation in the fixed-column form implies z times the determinant retaining columns r^28,…,r^2,r plus the determinant retaining columns r^28,…,r^2,1 is zero. This is a necessary determinant relation and does not identify the source-specific E-polynomial arrays or the selected criticalRoot lift.
References
- Truth anchor:
D5/S3/Observer/CubicGain/ExactW3Center.criticalRoot_spec - Truth anchor:
D5/S3/Observer/CubicGain/ExactW3Center.critical_root_exists - Truth anchor:
D5/S3/Observer/CubicGain/ExactW3Center.exactW3_parent - Truth anchor:
D5/S3/Observer/CubicGain/ExactW3Center.exactW3_parent_of_source_certificate - Truth anchor:
D5/S3/Observer/CubicGain/ExactW3Center.fixed_minor_linear_relation - Dependency: D5/S3/Observer/CubicGain/RegularParentChart
- Dependency: D5/S3/Observer/CubicGain/RegularReadInverse