Pretty cool. I would think there would either be an algorithm to label the vertices or an example of one that cannot be elegantly labelled, but I guess not. I's

Pretty cool. I would think there would either be an algorithm to label the vertices or an example of one that cannot be elegantly labelled, but I guess not. I's pretty obvious that node n must be adjacent to node 0, since that's the only way to get edge n. And it's pretty obvious that if you have one labeling you can get another by replacing m with n-m, so all the edges keep the same labels. But that's about as far as I get.