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LeanPool.BrillNoetherGraphs.LowGenus.GenusFiveCoreAtlas

The Atanasov--Ranganathan genus-five cubic atlas #

This is the public-layer transcription of the sixteen loopless, bridgeless, topologically trivalent graphs displayed in Figure 8 of Atanasov--Ranganathan. It contains only incidence data and kernel-checked elementary properties; it does not assert the classification theorem or any divisor construction.

The vertices 0, ..., 7 follow the TikZ node order. Parallel TikZ edges are separate ordered slots. The source contains stray self-loop draw commands in the twelfth and sixteenth scopes; both scopes are already cubic with twelve non-loop edges, so those commands are omitted, as the figure caption requires.

@[reducible, inline]

An ordered genus-five core with eight vertices and twelve edge slots.

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    Number of half-edge incidences at a vertex of a loopless ordered core.

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      Every vertex has exactly three incident half-edges in the ordered core.

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        Every edge slot has two distinct endpoints.

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          Figure scope 1 (a6,b6,c6,d6,x,y,e6,f6).

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            Figure scope 2 (a9,b9,c9,b9a,c9a,d9,e9,f9).

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              Figure scope 3 (41,42,43,45,A3,A5,B3,B5).

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                Figure scope 4 (A1,A2,A8,A7,A3,A4,A5,A6).

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                  Figure scope 5 (a6,b6,c6,d6,x,y,e6,f6).

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                    Figure scope 6 (a6,b6,c6,d6,e6,f6,q6,p6).

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                      Figure scope 7 (41,42,43,45,B1,B2,B3,B4).

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                        Figure scope 8 (a6,b6,c6,j6,d6,h6,e6,f6).

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                          Figure scope 9 (31,32,33,34,35,36,311,312).

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                            Figure scope 10 (31,32,33,34,35,36,37,38).

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                              Figure scope 11 (outer square and inner square).

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                                Figure scope 12, omitting the anomalous extra self-loop command.

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                                  Figure scope 13 (two K₄-minus-edge blocks).

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                                    Figure scope 14 (a,b,c,d,e,f,g,h).

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                                      Figure scope 15, with cyclic vertex labels O1, ..., O8.

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                                        Figure scope 16, omitting the anomalous extra self-loop command.

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                                          Connectivity #

                                          All sixteen rows, in one place. Six of them (01, 02, 04, 05, 08, 10) used to be proved locally in the row and chamber files instead — nine copies in all, because rows 08 and 10 repeated the fact once per chamber — and GenusFiveCubicAtlas re-proved the same six inline. They were kept out of here only because touching this file invalidates the forty-six modules that import it, including every generated cover; the generated covers now build

                                          /-! # Genus Five Core Atlas -/ only in the independent generated checks.

                                          The checker is connectedCheckFast (Utilities/Subdivision/ConnectedCheckFast.lean): a union--find fold rather than an enumeration of all 2⁸ vertex subsets. Measured on exactly these sixteen cores, the old connectedCheck cost 0.52 s each and this costs 0.013 s.

                                          The cube row is connected. This small public fact lets its readable AR construction use the closed-subdivision rank-determining-set theorem without importing the private generated atlas.