| 1. | If G is a planar graph, then 2 T G ( 3 , 3 ) {\displaystyle 2T_{G}(3,3)} equals the sum over weighted Eulerian orientations in a medial graph of G, where the weight of an orientation is 2 to the number of saddle vertices of the orientation (that is, the number of vertices with incident edges cyclicly ordered "in, out, in out").
Si G est un graphe planaire, alors 2 T G ( 3 , 3 ) |
