In graph theory, the degree diameter problem is the problem of finding the largest possible graph for a given maximum degree and diameter. The Moore bound sets limits on this, but for many years mathematicians in the field have been interested in a more precise answer. The table below gives current progress on this problem (excluding the case of degree 2, where the largest graphs are cycles with an odd number of vertices).
Table of the orders of the largest known graphs for the undirected degree diameter problem Below is the table of the vertex numbers for the best-known graphs (as of June 2024) in the undirected degree diameter problem for graphs of degree at most 3 ≤ d ≤ 16 and diameter 2 ≤ k ≤ 10. Only a few of the graphs in this table (marked in bold) are known to be optimal (that is, largest possible). The remainder are merely the largest so far discovered, and thus finding a larger graph that is closer in order (in terms of the size of the vertex set) to the Moore bound is considered an open problem. Some general constructions are known for values of d and k outside the range shown in the table.
Entries without a footnote were found by Loz & Širáň (2008). In all other cases, the footnotes in the table indicate the origin of the graph that achieves the given number of vertices:
References Abas, Marcel (2016), "Cayley graphs of diameter two with order greater than 0.684 of the Moore bound for any degree", European Journal of Combinatorics, 57: 109–120, arXiv:1511.03706, doi:10.1016/j.ejc.2016.04.008 Alegre, Ignacio; Fiol, Miquel; Yebra, J. Luis A. (1986), "Some Large Graphs with Given Degree and Diameter", Journal of Graph Theory, 10 (2): 219–224, doi:10.1002/jgt.3190100211 Allwright, James (1992), "New (Δ, D) graphs discovered by heuristic search", Discrete Applied Mathematics, 37–38: 3–8, doi:10.1016/0166-218X(92)90120-Y Bermond, Jean-Claude; Delorme, Charles; Farhi, Guy (1982), "Large Graphs with Given Degree and Diameter III" (PDF), Graph Theory, Proceedings of the Conference on Graph Theory, North-Holland Mathematics Studies, vol. 62, pp. 23–31, doi:10.1016/S0304-0208(08)73544-8, ISBN 9780444864499, S2CID 118362048 Also published in Annals of Mathematics (1982) 13 23–31. Buset, Dominique (2000), "Maximal cubic graphs with diameter 4", Discrete Applied Mathematics, 101 (1–3): 53–61, doi:10.1016/S0166-218X(99)00204-8 Canale, Eduardo; Rodríguez, Alexis (2012), On the application of voltage graphs to the degree/diameter problem (PDF), archived from the original (PDF) on 2020-09-28 Comellas, Francesc; Gómez, José (1994). "New Large Graphs with Given Degree and Diameter". arXiv:math/9411218. Comellas, Francesc (2024). "Table of large graphs with given degree and diameter". arXiv:2406.18994 [math.CO]. Conder, Marston (2006). "Trivalent (cubic) symmetric graphs on up to 2048 vertices". Delorme, Charles; Farhi, Guy (1984), "Large Graphs with Given Degree and Diameter - Part I", IEEE Transactions on Computers, 33 (9): 857–860, Bibcode:1984ITCmp.100..857D, doi:10.1109/TC.1984.1676504 Delorme, Charles (1985a), "Grands Graphes de Degré et Diamètre Donnés", European Journal of Combinatorics, 6 (4): 291–302, doi:10.1016/S0195-6698(85)80043-3 Delorme, Charles (1985b), "Large bipartite graphs with given degree and diameter", Journal of Graph Theory, 9 (3): 325–334, doi:10.1002/jgt.3190090304, S2CID 21199003 Dinneen, Michael J.; Hafner, Paul R. (1994), "New Results for the Degree/Diameter Problem", Networks, 24 (7): 359–367, arXiv:math/9504214, doi:10.1002/net.3230240702, S2CID 26375247 Doty, Karl (1982), "Large regular interconnection networks", Proceedings of the 3rd International Conference on Distributed Computing Systems, IEEE Computer Society, pp. 312–317 Elspas, Bernard (1964), "Topological constraints on interconnection-limited logic", 1964 Proceedings of the Fifth Annual Symposium on Switching Circuit Theory and Logical Design, pp. 133–137, doi:10.1109/SWCT.1964.27 Gómez, José (2009), "Some new large (Δ, 3)-graphs", Networks, 53 (1): 1–5, doi:10.1002/NET.V53:1 Gómez, José; Fiol, Miquel (1985), "Dense compound graphs", Ars Combinatoria, 20: 211–237 Gómez, José; Fiol, Miquel; Serra, Oriol (1993), "On large (Δ,D)-graphs", Discrete Mathematics, 114 (1–3): 219–235, doi:10.1016/0012-365X(93)90368-4 Hoffman, Alan J.; Singleton, Robert R. (1960), "Moore graphs with diameter 2 and 3", IBM Journal of Research and Development, 5 (4): 497–504, doi:10.1147/rd.45.0497, MR 0140437 Loz, Eyal; Širáň, Jozef (2008), "New record graphs in the degree-diameter problem" (PDF), Australasian Journal of Combinatorics, 41: 63–80 McKay, Brendan D.; Miller, Mirka; Širáň, Jozef (1998), "A note on large graphs of diameter two and given maximum degree", Journal of Combinatorial Theory, Series B, 74 (4): 110–118, doi:10.1006/jctb.1998.1828 Miller, Mirka; Širáň, Jozef (2013), "Moore graphs and beyond: A survey of the degree/diameter problem", Electronic Journal of Combinatorics, Dynamic survey D Molodtsov, Sergey (2006), General Theory of Information Transfer and Combinatorics, Springer, pp. 853–857, ISBN 978-3-540-46244-6 Pineda-Villavicencio, Guillermo; Gómez, José; Miller, Mirka; Pérez-Rosés, Hebert (2006), "New Largest Graphs of Diameter 6", Electronic Notes in Discrete Mathematics, 24: 153–160, doi:10.1016/j.endm.2006.06.044, hdl:1959.17/67691 Sampels, Michael (1997), "Large Networks with Small Diameter", Graph-Theoretic Concepts in Computer Science, Lecture Notes in Computer Science, vol. 1335, Springer, Berlin, Heidelberg, pp. 288–302, doi:10.1007/BFb0024505, ISBN 978-3-540-69643-8 Storwick, Robert (1970), "Improved Construction Techniques for (d, k) Graphs", IEEE Transactions on Computers, C-19 (12): 1214–1216, Bibcode:1970ITCmp.100.1214S, doi:10.1109/T-C.1970.222861 Wegner, Gerd (1977), Graphs with given diameter and a coloring problem (PDF), Technische Universität Dortmund, doi:10.17877/DE290R-16496
External links The Degree-Diameter Problem on CombinatoricsWiki.org. Eyal Loz's degree-diameter problem page (archived 2016.) Geoffrey Exoo's degree-diameter record graphs page (archived 2015.)
