2-walks in 3-connected Planar Graphs

In this we prove that every 3-connected planar graph has closed walk each vertex, none more than twice, such that any vertex visited twice is in a vertex cut of size 3. This both Tutte's Theorem that 4-connected planar graphs are Hamiltonian and the result of Gao and Richter that 3-connected planar graphs have a closed walk visiting each vertex at least once but at most twice.

[1]  Bill Jackson,et al.  K-walks of Graphs , 1990, Australas. J Comb..

[2]  Zhicheng Gao,et al.  Spanning Planar Subgraphs of Graphs in the Torus and Klein Bottle , 1995, J. Comb. Theory, Ser. B.

[3]  W. T. Tutte A THEOREM ON PLANAR GRAPHS , 1956 .

[4]  D. Barnette Trees in Polyhedral Graphs , 1966, Canadian Journal of Mathematics.

[5]  Carsten Thomassen,et al.  A theorem on paths in planar graphs , 1983, J. Graph Theory.