The three rational quartic-plane orbits #
This file finishes the coordinate part of the low--low quartic exclusion.
The only finite certificate is the left inverse in CubicDirect; the orbit
arguments below are ordinary exterior algebra and coordinate extensionality.
Select evaluation at infinity among the three rational-place coordinates.
Instances For
The sum of the evaluation-at-one and evaluation-at-infinity coordinates.
Equations
Instances For
The sum of the evaluation-at-zero and evaluation-at-one coordinates.
Equations
Instances For
The sum of the evaluation-at-zero and evaluation-at-infinity coordinates.
Equations
Instances For
Orbit span(r₀,r₁+r∞): the coefficient of the second generator
vanishes, and the remaining coefficient lies in P₀.
Orbit span(r₀+r₁,r₀+r∞): cubic cancellation kills both linear
differences.
Shared quadratic-shadow argument for the three low--low quartic
orbits. Its hypotheses are exactly the output of the cubic direct-sum
calculation: the two linear differences lie in P₁ and P₀, and their
cubic contractions vanish.
Low--low quartic collision for the orbit
span(r₀,r₁+r∞).
Low--low quartic collision for the orbit
span(r₀+r₁,r₀+r∞).