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Gerhard Paseman
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I don't know. The following is a near miss which might be useful.

Start with a hexagonal cycle path ABCDEFA. Duplicate point C to C' and connect C' to B,C, and D. Similarly duplicate points E and F, and add edges EE', FF', and the 3 edges to form the path DE'F'A. Then it has diameter 3, but the only point that is distance 3 from E (and also from E') is B, so it cannot accomdate such a permutation. The only problem is that vertex D has degree 4, so the graph is just shy of being 3-regular.

It may be possible to use this by stitching together two large even cycles to get a regular graph (with the property that two vertices must share an antipode), but I will let someone else do it.

Gerhard "Cycles Can Make Me Dizzy" Paseman, 2011.05.11

Gerhard Paseman
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