“…Roughly speaking, a partial dual is obtained by forming the geometric dual with respect to only a subset of edges of an embedded graph (a formal definition is given Subsection 2.3). Partial duality appears to be a fundamental operation on embedded graphs and, although it has only recently been introduced, it has found a number of applications in graph theory, topology, and physics (see, for example, [3,5,6,8,9,10,11,12,14,15]). While geometric duality always preserves the surface in which a graph is embedded, this is not the case for the more general partial duality.…”