What does it mean that a graph dual is not unique, because the dual depends on the particular embedding?
I don't get what graph embeddings are and how they're related to the uniqueness of the dual.
Particularly, is drawing the dual meant to be done in planar sense? That one considers as if the graph was projected on to a plane? So one is able to cross edges once in only a particular way, whereas in a "space" representation I don't think the embedding would matter, since one'd always draw through the edges the same way.