Abstract
Some researchers have proved that ádám’s conjecture is wrong. However, under special conditions, it is right. Let Zn be a cyclic group of order n and Cn(S) be the circulant digraph of Zn with respect to S ⊆ Zn\{0}. In the literature, some people have used a spectral method to solve the isomorphism for the circulants of prime-power order. In this paper, we also use the spectral method to characterize the circulants of order paqbwc(where p, q and w are all distinct primes), and to make ádám’s conjecture right.
Similar content being viewed by others
References
Ádám, A. Research problem 2–10. Combinatorial Theory, Series B, 2: 393 (1967)
Alspach, B., Parsons, T.D. Isomorphism of circulant graphs and digraphs. Discrete Mathematics, 25: 97–108 (1979)
Alspach, B. Isomorphism and Cayley graphs on abelian groups. Graph Symmetry, 497: 1–22 (1997)
Baibai, L. Isomorphism problem for a class of point-symmetric structures. Acta Mathematica Hungarica, 29: 329–336 (1977)
Djoković, D.Ź. Isomorphism problem for a special class of graphs. Acta Mathematica Hungarica, 21: 267–270 (1970)
Elspas, B., Turner, J. Graphs with circulant adjacency matrices. Combinatorial Theory, 9: 297–307 (1970)
Huang, Q., Meng, J. On the isomorphisms and automorphism groups of circulants. Graphs and Combinatorics, 12: 179–187 (1996)
Huang, Q., Meng, J. A classification of DCI(CI)-subsets for cyclic group of odd prime power order. Combinatorial Theory, Series B, 78: 24–34 (2000)
Huang, Q., An, C. Circulant digraphs determined by their spectra. Discrete Mathematics, 240: 261–270 (2001)
Klin, M.H., Pöschel, R. The isomorphism problem for circulant digraphs with pn vertices. preprint P34/80, AdWDDR, ZIMM, Berlin, 40p, 1980
Li, C. On the isomorphism of connected Cayley graphs. Discrete Mathematics, 78: 109–122 (1998)
Li, C. Isomorphism of connected Cayley graphs. Graphs and Combinatorics, 14: 37–44 (1998)
Meng, J., Huang, Q. The automorphism groups of minimal infinite circulant digraphs. European Combinatorics, 18: 425–429 (1997)
Muzychuk, M., Ádám’s, A. Conjecture is true in the square-free case. Combinatorial Theory. Series A, 72: 118–143 (1995)
Muzychuk, M. On Ádám’s conjecture for circulant graphs. Discrete Math., 167/168: 497–501 (1997)
Turner, J. Point symmetric groups with a prime number of points. Combinatorial Theory, 3: 136–145 (1967)
Toida, S. A note on Ádám’s conjecture. Combinatorial Theory. Series B, 23: 239–246 (1977)
Biggs, N.L. Algebraic Graph Theory. Cambridge University Press, Cambridge, 1974
Author information
Authors and Affiliations
Corresponding author
Additional information
The research is supported by Start high-level personnel of scientific research funds of Jiangsu Second Normal University (No. 918001) and NSFC(11171283).
Rights and permissions
About this article
Cite this article
Qin, Zx., Meng, Jx. & Huang, Qx. A Classification of Spectrum-determined Circulant Digraphs. Acta Math. Appl. Sin. Engl. Ser. 34, 703–709 (2018). https://doi.org/10.1007/s10255-018-0778-0
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10255-018-0778-0