2 papers
math.CO2020
Flips on homologous orientations of surface graphs with prescribed forbidden facial circuits
Weijuan Zhang, Jianguo Qian
Let be a graph embedded on an orientable surface. Given a class of facial circuits of as a forbidden class, we give a sufficient-necessary condition for that an…
math.CO2017
Flip-distance between α-orientations of graphs embedded on plane and sphere
Weijuan Zhang, Jianguo Qian, Fuji Zhang
Felsner introduced a cycle reversal, namely the `flip' reversal, for α-orientations (i.e., each vertex admits a prescribed out-degree) of a graph G embedded on the plane and furthe…