Documentation

LeanPool.BooleanMultiplication.N4.QuarticIdempotenceConsequences

Consequences of the quartic idempotence equation #

The nine-coordinate bridge is applied to an equation F * c = F, where F is affine plus a Hankel target and c is affine plus a rational target. Every summand except target times rational has degree at most three, so the quartic equation is exactly the rational-annihilator probe.

theorem UnrestrictedBooleanMul.N4.quartic_data_of_right_idempotence {F c : ANF 8} (hFAmbient : F ∈ targetAmbient 8 (mulTarget 4)) (hFNotLow : F ∉ rationalLowSpace) (hcLow : c ∈ rationalLowSpace) (hFc : F * c = F) :
∃ (a : F₂) (b : F₂) (ell : LinearForm) (m : LinearForm) (C : TargetCoeff) (delta : Fin 3 → F₂), F = affineANF a ell + targetANF C ∧ c = affineANF b m + rationalANF delta ∧ ¬IsRationalCoeff C ∧ VanishesOnQuarticAnnihilatorProbe C delta

Normal forms extracted from the right idempotence equation. The target coefficient is nonrational because F lies outside the rational-low state, and its quartic product with the rational part of c vanishes.