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.
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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- AtanasovRanganathan.GenusFiveCoreAtlas.Trivalent core = ∀ (vertex : Fin 8), AtanasovRanganathan.GenusFiveCoreAtlas.incidenceDegree core vertex = 3
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Every edge slot has two distinct endpoints.
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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 first displayed row, AR's first family, is connected.
The second displayed row, AR's second family, is connected.
The necklace row, AR's fourth family, is connected.
The sixth-family row is connected.
The configuration-5 row is connected.
The seventh-family row is connected.
The ninth-family row is connected.
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.
The twelfth displayed row is connected.
The two-block row is connected.
The Möbius-ladder row is connected.
The final displayed row is connected.