Uniqueness conjecture for the toroidal penny graph embedding of K3,3K_{3,3}

About 2 years old · traced to

A toroidal penny graph is a contact graph of congruent non-overlapping disks embedded on a flat torus, with vertices representing disk centers and edges representing tangent pairs. Consider the embedding of K3,3K_{3,3} whose toroidal coordinates are given by

(1336,−1336),(1136,136),(136,1136),(−1336,1336),(−1136,−136),(−136,−1136).\left(\frac{13}{36},-\frac{13}{36}\right), \left(\frac{11}{36},\frac{1}{36}\right), \left(\frac{1}{36},\frac{11}{36}\right), \left(-\frac{13}{36},\frac{13}{36}\right), \left(-\frac{11}{36},-\frac{1}{36}\right), \left(-\frac{1}{36},-\frac{11}{36}\right).

Uniqueness conjecture for the K3,3K_{3,3} embedding. The proposed embedding of K3,3K_{3,3}, with coordinates as described in the table, is unique up to an isometry.

The claim concerns the rigidity of the exhibited toroidal penny graph realization of K3,3K_{3,3}: no non-isometric embedding with the same graph is expected to exist. The source provides the embedding and its packing radius but gives no resolution of this uniqueness question.

References

Primary source

Cédric Lorand, “K5 and K3,3 are Toroidal Penny Graphs”, arXiv:2410.10673 (2024).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.