Abstract
In 1988, Seiya Negami published a conjecture stating that a graph G has a finite planar cover (i.e. a homomorphism from some planar graph onto G which maps the vertex neighbourhoods bijectively) if and only if G embeds in the projective plane. Though the “if” direction is easy, and over ten related research papers have been published during the past 20 years of investigation, this beautiful conjecture is still open in 2008. We give a short accessible survey on Negami’s conjecture and all the (so far) published partial results, and outline some further ideas to stimulate future research towards solving the conjecture.
Similar content being viewed by others
References
Archdeacon D.: A Kuratowski theorem for the projective plane. J. Graph Theory 5, 243–246 (1981)
Archdeacon D.: Two graphs without planar covers. J. Graph Theory 41, 318–326 (2002)
Archdeacon D., Richter R.B.: On the parity of planar covers. J. Graph Theory 14, 199–204 (1990)
Fellows, M. Encoding Graphs in Graphs. Ph.D. Dissertation, University of California, San Diego (1985)
Fellows, M.: Planar Emulators and Planar Covers. Manuscript (1988)
Glover H., Huneke J.P., Wang C.S.: 103 Graphs that are irreducible for the projective plane. J. Comb. Theory Ser. B 27, 332–370 (1979)
Hliněný P.: K 4,4−e has no finite planar cover. J. Graph Theory 27, 51–60 (1998)
Hliněný P.: A note on possible extensions of Negami’s Conjecture. J. Graph Theory 32, 234–240 (1999)
Hliněný, P.: Planar Covers of Graphs: Negami’s Conjecture, Ph.D. Dissertation, Georgia Institute of Technology, Atlanta (1999)
Hliněný P.: Another two graphs having no planar covers. J. Graph Theory 37, 227–242 (2001)
Hliněný P., Thomas R.: On possible counterexamples to Negami’s planar cover conjecture. J. Graph Theory 46, 183–206 (2004)
Huneke, J.P.: A Conjecture in topological graph theory. In: Robertson, N., Seymour, P.D. (eds.) Graph Structure Theory (Seattle, WA, 1991). Contemporary Mathematics, vol. 147, pp. 387–389 (1993)
Kitakubo S.: Planar branched coverings of graphs. Yokohama Math. J. 38, 113–120 (1991)
Mohar, B., Thomassen, C. Graphs on surfaces. Johns Hopkins Studies in the Mathematical Sciences. Johns Hopkins University Press, Baltimore (2001)
Negami S.: Enumeration of projective-planar embeddings of graphs. Discrete Math. 62, 299–306 (1986)
Negami S.: The spherical genus and virtually planar graphs. Discrete Math. 70, 159–168 (1988)
Negami S.: Graphs which have no finite planar covering. Bull. Inst. Math. Acad. Sin. 16, 378–384 (1988)
Negami S., Watanabe T.: Planar cover conjecture for 3-regular graphs. J. Faculty Educ. Human Sci. Yokohama Natl. Univ. 4, 73–76 (2002)
Negami S.: Composite planar coverings of graphs. Discrete Math. 268, 207–216 (2003)
Negami S.: Projective-planar double coverings of graphs. Eur. J. Comb. 26, 325–338 (2005)
Rieck Y., Yamashita Y.: Finite planar emulators for K 4,5−4K 2 and K 1,2,2,2 and Fellows’ Conjecture. Eur. J. Comb. 31(3), 903–907 (2010)
Author information
Authors and Affiliations
Corresponding author
Additional information
Supported by the Czech research grant GAČR 201/08/0308 and by the Institute for Theoretical Computer Science, project 1M0545.
Rights and permissions
About this article
Cite this article
Hliněný, P. 20 Years of Negami’s Planar Cover Conjecture. Graphs and Combinatorics 26, 525–536 (2010). https://doi.org/10.1007/s00373-010-0934-9
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00373-010-0934-9