Abstract
A graph G is said to be 1-planar if it can be drawn on the sphere or plane so that any edge of G has at most one crossing point with another edge. Moreover, G is called an optimal 1-planar graph if \(|E(G)| = 4|V(G)|-8\). In this paper, we investigate the matching extendability of optimal 1-planar graphs. It is shown that every optimal 1-planar graph G of even order is 2-extendable unless G contains a 4-cycle C which separates the graph into two odd components. Moreover, for any 5-connected optimal 1-planar graph, we characterize a matching with three edges which is not extendable.
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Aldred, R.E.L., Kawarabayashi, K., Plummer, M.D.: On the matching extendability of graphs in surfaces. J. Comb. Theory Ser. B 98, 105–115 (2008)
Aldred, R.E.L., Plummer, M.D.: Edge proximity and matching extension in planar triangulations. Australas. J. Comb. 29, 215–224 (2004)
Aldred, R.E.L., Plummer, M.D.: Proximity thresholds for matching extension in planar and projective planar triangulations. J. Graph Theory 67, 38–46 (2011)
Auer, C., Bachmaier, C., Brandenburg, F.J., Gleißner, A., Hanauer, K., Neuwirth, D., Reislhuber, J.: Outer 1-planar graphs. Algorithmica 74, 1293–1320 (2016)
Chen, Z.-Z., Kouno, M.: A linear-time algorithm for 7-coloring 1-plane graphs. Algorithmica 43, 147–177 (2005)
Czap, J., Hudák, D.: On drawings and decompositions of 1-planar graphs. Electron. J. Combin. 20(2), 54 (2013)
Diestel, R.: Graph Theory. Graduate Texts in Mathematics, vol. 173, 4th edn. Springer, Heidelberg (2010)
Fabrici, I., Madaras, T.: The structure of 1-planar graphs. Discrete Math. 307, 854–865 (2007)
Kawarabayashi, K., Negami, S., Plummer, M.D., Suzuki, Y.: The 2-extendability of 5-connected graphs on surfaces with large representativity. J. Comb. Theory Ser. B 101, 206–213 (2011)
Korzhik, V.P., Mohar, B.: Minimal obstructions for 1-immersions and hardness of 1-planarity testing. J. Graph Theory 72, 30–71 (2013)
Noguchi, K., Suzuki, Y.: Relationship among triangulations, quadrangulations and optimal 1-planar graphs. Graphs Comb. 31, 1965–1972 (2015)
Plummer, M.D.: A theorem on matchings in the plane. Ann. Discrete Math. 41, 347–354 (1989)
Plummer, M.D.: Extending matchings in planar graphs IV. Discrete Math. 109, 207–219 (1992)
Plummer, M.D.: Recent Progress in Matching Extension, Building Bridges. Bolyai Society Mathematical Studies, vol. 19, pp. 427–454. Springer, Berlin (2008)
Ringel, G.: Ein Sechsfarbenproblem auf der Kugel. Abh. Semin. Univ. Hamburg 29, 107–117 (1965)
Suzuki, Y.: Re-embeddings of maximum 1-planar graphs. SIAM J. Discrete Math. 24, 1527–1540 (2010)
Thomas, R., Yu, X.: 4-connected projective-planar graphs are Hamiltonian. J. Comb. Theory Ser. B 62, 114–132 (1994)
Acknowledgements
The authors would like to thank Katsuhiro Ota whose comment led to significant improvement in the proof of Lemma 4.
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J. Fujisawa: Partly supported by Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B) 16H03952 and (C) 17K05349 and Grant-in-Aid for Young Scientists (B) 26800085.
Y. Suzuki: Partly supported by Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C) 16K05250.
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Fujisawa, J., Segawa, K. & Suzuki, Y. The Matching Extendability of Optimal 1-Planar Graphs. Graphs and Combinatorics 34, 1089–1099 (2018). https://doi.org/10.1007/s00373-018-1932-6
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DOI: https://doi.org/10.1007/s00373-018-1932-6