Remarks about the Moebius-Kantor graph
This paper provides a mathematical characterization of the Moebius-Kantor graph and its relationship to specific algebraic structures, which is of interest to researchers in topological graph theory and group theory.
The Moebius-Kantor graph (MK) is a Cayley graph for three non-abelian groups (Pauli, semi-dihedral, and dihedral groups of order 16). The authors computed Lefschetz numbers to illustrate the Brouwer-Lefschetz fixed point theorem and found that MK has only one algebraic group structure (P(1),*) that preserves its metric.
The Moebius-Kantor graph MK=G(8,3) is a Cayley graph of three non-abelian groups, the Pauli group P(1), the semi-dihedral group SD(16), as well as the dihedral group D(16) of order 16. In topological graph theory, it illustrates the Heawood number 7 of the torus and leads to the Tucker group Aut(MK), the unique group of genus 2. We compute the Lefschetz numbers to illustrate the Brouwer-Lefschetz fixed point theorem. MK is also the dual of the 2-skeleton complex of the 3-sphere G. The graph represents one of flat Clifford tori of a Hopf fibration in the 3-sphere G=K(2,2,2,2) reflecting that Coxeter saw that MK is a subgraph of the tesseract G*. It carries a metric d so that (MK,d) has only one algebraic group structure (P(1),*) that preserves the metric. It makes the Pauli group natural, similarly as the Moebius ladder M(16) makes the dihedral group D(16) natural, forcing the algebraic structure from the metric structure.