Articulation data for the four genus-five cubic bridge rows #
All four exceptional rows in the public cubic atlas have the same labelled
genus-two lobe on vertices {0,1,2}, attached to the complementary
genus-three side at vertex 0. The occurrence-level core cut checker and
the factor-genus calculator verify this finite structural data directly.
The root-double bridge cut, with gluing vertex zero and left vertex set {0, 1, 2}.
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The one-chord bridge cut, with gluing vertex zero and left vertex set {0, 1, 2}.
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The square bridge cut, with gluing vertex zero and left vertex set {0, 1, 2}.
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The double-matching bridge cut, with gluing vertex zero and left vertex set {0, 1, 2}.
Equations
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A checked (2,3) articulation on a genus-five core supplies a
degree-four pencil on every nonloopy forest face of that core.
The four bridge rows are all closed structurally by the same checked
(2,3) articulation.