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PolygonalArcCollarOrientedSeparatedTubeData

Definition
PolygonalArcCollarOrientedSeparatedTubeData

by xuanji · Sep 27, 2026 · Mathlib 0df444a (Lean v4.33.1)

crossing-consequencesgeometrypolygonal

A separated polygonal-arc collar tube system whose normal vectors are fixed to be the positive quarter-turns of the corresponding edge directions.

Definition code
import Definitions.Def_PolygonalArcCollarSeparatedTubeData

-- [TABLET NODE: PolygonalArcCollarOrientedSeparatedTubeData]
-- Source: https://github.com/wpegden/crossing-consequences/blob/8769d142033fce042f502bf2857afb6b1375b5c3/Tablet/PolygonalArcCollarOrientedSeparatedTubeData.lean#L1-18
structure PolygonalArcCollarOrientedSeparatedTubeData (γ : PolygonalArc) {η : ℝ}
    (controlRadii : PolygonalArcCollarControlRadii γ η)
    (middleSegments : PolygonalArcCollarMiddleSegmentData γ controlRadii)
    (forbiddenMargins :
      PolygonalArcCollarMiddleForbiddenMargins γ controlRadii middleSegments)
    extends
      PolygonalArcCollarSeparatedTubeData γ controlRadii middleSegments
        forbiddenMargins where
  normal_eq_positive_quarter_turn :
    ∀ (j : ℕ) (hj : j + 1 < γ.vertices.length),
      normal j hj =
        WithLp.toLp 2 (fun k : Fin 2 =>
          if k = 0 then -((γ.vertices[j + 1] - γ.vertices[j]) 1)
          else (γ.vertices[j + 1] - γ.vertices[j]) 0)
Source
https://github.com/wpegden/crossing-consequences/blob/8769d142033fce042f502bf2857afb6b1375b5c3/Tablet/PolygonalArcCollarOrientedSeparatedTubeData.lean#L1-18

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