Abstract
A graph is n-existentially closed (n-e.c.) if for any disjoint subsets A, B of vertices with \(\left| {A \cup B} \right| =n\), there is a vertex \(z \notin A \cup B\) adjacent to every vertex of A and no vertex of B. For a block design with block set \({\mathcal {B}}\), its block intersection graph is the graph whose vertex set is \({\mathcal {B}}\) and two vertices (blocks) are adjacent if they have non-empty intersection. In this paper, we investigate the block intersection graphs of pairwise balanced designs, and propose a sufficient condition for such graphs to be 2-e.c. In particular, we study the \(\lambda \)-fold triple systems with \(\lambda \ge 2\) and determine for which parameters their block intersection graphs are 1- or 2-e.c. Moreover, for Steiner quadruple systems, the block intersection graphs and their analogue called \(\{1\}\)-block intersection graphs are investigated, and the necessary and sufficient conditions for such graphs to be 2-e.c. are established.
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Ananchuen, W., Caccetta, L.: On the adjacency properties of Paley graphs. Networks 23(4), 227–236 (1993)
Baker, C.A., Bonato, A., Brown, J.M.N.: Graphs with the \(3\)-e.c. adjacency property constructed from affine planes. J. Combin. Math. Combin. Comput. 46, 65–83 (2003)
Baker, C.A., Bonato, A., Brown, J.M.N., Szőnyi, T.: Graphs with the \(n\)-e.c. adjacency property constructed from affine planes. Discrete Math. 308(5–6), 901–912 (2008)
Beth, T., Jungnickel, D., Lenz, H.: Design Theory Vol. 1, Encyclopedia Math. Appl., vol. 69, 2nd edn. Cambridge University Press, Cambridge (1999)
Blass, A., Exoo, G., Harary, F.: Paley graphs satisfy all first-order adjacency axioms. J. Graph Theory 5(4), 435–439 (1981)
Bollobás, B., Thomason, A.: Graphs which contain all small graphs. Eur. J. Combin. 2(1), 13–15 (1981)
Bonato, A.: The search for \(n\)-e.c. graphs. Contrib. Discrete Math. 4(1), 40–53 (2009)
Bonato, A., Cameron, K.: On an adjacency property of almost all graphs. Discrete Math. 231(1–3), 103–119 (2001)
Bonato, A., Holzmann, W.H., Kharaghani, H.: Hadamard matrices and strongly regular graphs with the \(3\)-e.c. adjacency property. Electron. J. Combin. 8(1), R1 (9pp) (2001)
Cameron, P.J.: The random graph. In: The Mathematics of Paul Erdős II, Algorithms Combin., vol. 14, pp. 333–351. Springer, New York (1997)
Colbourn, C.J., Dinitz, J.H. (eds.): Handbook of Combinatorial Designs, 2nd edn. CRC Press, Boca Raton (2007)
Colbourn, C.J., Forbes, A.D., Grannell, M.J., Griggs, T.S., Kaski, P., Östergård, P.R., Pike, D.A., Pottonen, O.: Properties of the Steiner triple systems of order 19. Electron. J. Combin. 17(1), #R98 (2010)
Colbourn, C.J., Rosa, A.: Triple Systems. Oxford University Press, Oxford (1999)
Dehon, M.: On the existence of \(2\)-designs \({S}_\lambda (2, 3, v)\) without repeated blocks. Discrete Math. 43(2–3), 155–171 (1983)
Erdős, P., Rényi, A.: Asymmetric graphs. Acta Math. Acad. Sci. Hungar. 14(3–4), 295–315 (1963)
Forbes, A., Grannell, M.J., Griggs, T.S.: Steiner triple systems and existentially closed graphs. Electron. J. Combin. 12(3), #R42 (2005)
Hanani, H.: On quadruple systems. Can. J. Math 12, 145–157 (1960)
Hartman, A., Phelps, K.T.: Steiner quadruple systems. In: J. Dinitz, D. Stinson (eds.) Contemporary Design Theory: A Collection of Surveys, chap. 6, pp. 205–240. Wiley, New York (1992)
Horsley, D., Pike, D.A., Sanaei, A.: Existential closure of block intersection graphs of infinite designs having infinite block size. J. Combin. Des. 19(4), 317–327 (2011)
Kaski, P., Östergård, P.R.: Classification Algorithms for Codes and Designs, Algorithms Comput. Math., vol. 15. Springer, New York (2006)
Kaski, P., Östergård, P.R.: Extra material for “Classification Algorithms for Codes and Designs”. http://extras.springer.com/2006/978-3-540-28990-6/ (2006). Accessed 25 Feb 2019
Kikyo, H., Sawa, M.: Köhler theory for countable quadruple systems. Tsukuba J. Math. 41(2), 189–213 (2017)
Köhler, E.: Allgemeine Schnittzahlen in \(t\)-designs. Discrete Math. 73(1–2), 133–142 (1989)
Lindner, C.C., Rosa, A.: Steiner quadruple systems—a survey. Discrete Math. 22(2), 147–181 (1978)
Mathon, R., Rosa, A.: Tables of parameters of BIBDs with \(r\le 41\) including existence, enumeration, and resolvability results. Ann. Discrete Math 26, 275–308 (1985)
McKay, N.A., Pike, D.A.: Existentially closed BIBD block-intersection graphs. Electron. J. Combin. 14(4), #R70 (2007)
Mendelsohn, N.S.: Intersection numbers of \(t\)-designs. In: L. Mirsky (ed.) Studies in Pure Mathematics, pp. 145–150. Academic Press, London (1971)
Mendelsohn, N.S., Hung, S.H.Y.: On the Steiner systems \(S(3,4,14)\) and \(S(4,5,15)\). Utilitas Math. 1, 5–95 (1972)
Pike, D.A., Sanaei, A.: Existential closure of block intersection graphs of infinite designs having finite block size and index. J. Combin. Des. 19(2), 85–94 (2011)
Piotrowski, W.: Notwendige Existenzbedingungen für Steinersysteme und ihre Verallgemeinerungen. Diplomarbeit Univ, Hamburg (1977)
Shen, H.: Embeddings of simple triple systems. Sci. China Ser. A 35(3), 283–291 (1992)
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This work was supported in part by JSPS under Grant-in-Aid for Scientific Research (B) No. 15H03636 and No. 18H01133.
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Lu, XN. Further Results on Existentially Closed Graphs Arising from Block Designs. Graphs and Combinatorics 35, 1323–1335 (2019). https://doi.org/10.1007/s00373-019-02036-z
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DOI: https://doi.org/10.1007/s00373-019-02036-z
Keywords
- Existential closure
- Block intersection graph
- Pairwise balanced design
- Triple system
- Steiner quadruple system