| proposed by | Toby Walsh tw@cs.york.ac.uk |
The diameter 5 problem has (ignoring roations and reflections) an unique solution
There is also a (trivial) diameter 1 magic hexagon. These are the only two sizes of magic hexagon possible.
Eliminating symmetry is important. The diameter 5 problem has 12 symmetries (rotation, reflection, ...) which need to be considered.