Analytic separators for sibling lens cells #
The off-matching coincident endpoint cell has a short global proof. Three norm tangents preserve the correlation between its cross distances. A rational two-by-two Gram majorant then separates the two colors, leaving a convex quadratic on the three radial vertices.
theorem
LeanPool.Besicovitch.offMatchingCoincidentTangentCertificate
{E : Type u_1}
[NormedAddCommGroup E]
[InnerProductSpace ℝ E]
(e p₁ p₂ w₁ w₂ : E)
(he : ‖e‖ = 1)
(hp₁ : ‖p₁‖ ≤ 1)
(hp₂ : ‖p₂‖ ≤ 1)
(hw₁ : ‖w₁‖ ≤ 1)
(hw₂ : ‖w₂‖ ≤ 1)
(hpsep : barC ≤ ‖p₁ - p₂‖)
(hwsep : barC ≤ ‖w₁ - w₂‖)
:
A global rational tangent separator for the off-matching coincident endpoint cell.
theorem
LeanPool.Besicovitch.offMatchingCoincidentLensBound_of_admissible
{configuration : SixPointConfiguration}
(h : configuration.IsAdmissibleAt barS)
:
OffMatchingCoincidentLensBound configuration
The off-matching coincident lens bound holds for every admissible configuration.
theorem
LeanPool.Besicovitch.not_redEndpoint_one_and_blueEndpoint_one
{configuration : SixPointConfiguration}
(h : configuration.IsAdmissibleAt barS)
(hmatching : SelectedDiagonalMatchingFails configuration)
:
¬(redSiblingTriangleFailure configuration (SiblingTriangleWitness.endpoint 1) ∧ blueSiblingTriangleFailure configuration (SiblingTriangleWitness.endpoint 1))
The off-matching coincident endpoint representative is impossible.