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Möbius-Kantor graph

There is a unique cubic symmetric (i.e., both vertex- and edge-transitive) graph on 16 vertices known as the Möbius-Kantor graph.

Construction

The Möbius-Kantor graph is the bipartite point-line incidence graph of the geometry with 8 points and 8 lines obtained by removing one point from the affine plane AG(2,3) of order 3.

Group

The group is GL(2,3).2 of order 96. It is vertex- and edge-transitive, with vertex stabilizer Sym(3).

Spectrum

The Möbius-Kantor graph has spectrum ±31, (±√3)4, ±13, and is the unique graph with this spectrum.

Distribution diagram

The graph is an antipodal 2-cover of the 3-cube.
It is the unique 2-cover of the 3-cube without quadrangles, cf. BCN 9.2.10.
One can add 8 edges and obtain the 4-cube (Coxeter).

Reference

H. S. M. Coxeter, Self-dual configurations and regular graphs, Bull. Amer. Math. Soc. 56 (1950) 413-455.