Abstract
In the 70 s, Berge introduced 1-extendable graphs (also called B-graphs), which are graphs where every vertex belongs to a maximum independent set. Motivated by an application in the design of wireless networks, we study the computational complexity of 1-extendability, the problem of deciding whether a graph is 1-extendable. We show that, in general, 1-extendability cannot be solved in \(2^{o(n)}\) time assuming the Exponential Time Hypothesis, where n is the number of vertices of the input graph, and that it remains NP-hard in subcubic planar graphs and in unit disk graphs (which is a natural model for wireless networks). Although 1-extendability seems to be very close to the problem of finding an independent set of maximum size (a.k.a. Maximum Independent Set), we show that, interestingly, there exist 1-extendable graphs for which Maximum Independent Set is NP-hard. Finally, we investigate a parameterized version of 1-extendability.







Similar content being viewed by others
References
Alekseev, V.E.: The effect of local constraints on the complexity of determination of the graph independence number. Comb. Algebr. Methods Appl. Math. 3–13 (1982)
Angaleeswari, K., Sumathi, P., Swaminathan, V.: \(k\)-extendability in graphs. Int. J. Pure Appl. Math. 101(5), 801–809 (2015)
Angaleeswari, K., Sumathi, P., Swaminathan, V.: Weakly \(k\)-extendable graphs. Int. J. Pure Appl. Math. 109(6), 35–40 (2016)
Berge, C.: Some common properties for regularizable graphs, edge-critical graphs and B-graphs. Graph Theory Algorithms Lect. Notes Comput. Sci. 108, 108–123 (1981)
Bonnet, É., Bousquet, N., Charbit, P., Thomassé, S., Watrigant, R.: Parameterized complexity of independent set in \(H\)-free graphs. Algorithmica 82(8), 2360–2394 (2020)
Bonnet, É., Bousquet, N., Thomassé, S., Watrigant, R.: When maximum stable set can be solved in FPT time. Proc. ISAAC 149, 49:1-49:22 (2019)
Chvátal, V., Slater, P. J.: A note on well-covered graphs. In: Quo Vadis, Graph Theory? Annals of Discrete Mathematics, vol. 55, pp. 179–181. Elsevier, Amsterdam (1993)
Clark, B.N., Colbourn, C.J., Johnson, D.S.: Unit disk graphs. Discret. Math. 86(1–3), 165–177 (1990)
Cygan, M., Fomin, F.V., Kowalik, L., Lokshtanov, D., Marx, D., Pilipczuk, M., Pilipczuk, M., Saurabh, S.: Parameterized Algorithms. Springer, Berlin (2015)
Dabrowski, K.K., Lozin, V.V., Müller, H., Rautenbach, D.: Parameterized complexity of the weighted independent set problem beyond graphs of bounded clique number. J. Discrete Algorithms 14, 207–213 (2012)
de Berg, M., Khosravi, A.: Optimal binary space partitions in the plane. Proc. COCOON 6196, 216–225 (2010)
Dean, N., Zito, J.S.: Well-covered graphs and extendability. Discret. Math. 126(1–3), 67–80 (1994)
Ducourthial, B., Mottelet, S., Busson, A.: Improving fairness between close Wi-Fi access points. J. Netw. Comput. Appl. 87, 87–99 (2017)
Finbow, A.S., Whitehead, C.A.: Constructions for well-covered graphs. Austral. J. Comb. 72(2), 273–289 (2018)
Garey, M.R., Johnson, D.S., Stockmeyer, L.J.: Some simplified NP-complete graph problems. Theor. Comput. Sci. 1(3), 237–267 (1976)
Grzesik, A., Klimosová, T., Pilipczuk, M., Pilipczuk, M.: Polynomial-time algorithm for maximum weight independent set on \(P_6\)-free graphs. In: Proceedings of SODA, pp. 1257–1271. SIAM (2019)
Hackfeld, J., Koster, A.: The matching extension problem in general graphs is co-NP-complete. J. Comb. Optim. 35(3), 853–859 (2018)
Impagliazzo, R., Paturi, R.: On the complexity of \(k\)-SAT. J. Comput. Syst. Sci. 62(2), 367–375 (2001)
Laufer, R., Kleinrock, L.: The capacity of wireless CSMA/CA networks. IEEE/ACM Trans. Netw. 24(3), 1518–1532 (2016)
Liew, S.C., Kai, C.H., Leung, H.C., Wong, P.: Back-of-the-envelope computation of throughput distributions in CSMA wireless networks. IEEE Trans. Mobile Comput. 9(9), 1319–1331 (2010)
Mohar, B.: Face covers and the genus problem for apex graphs. J. Comb. Theory Ser. B 82(1), 102–117 (2001)
Pilipczuk, M., Siebertz, S.: Kernelization and approximation of distance-r independent sets on nowhere dense graphs. Eur. J. Comb. 94, 103309 (2021)
Plummer, M.D.: Some covering concepts in graphs. J. Comb. Theory 8(1), 91–98 (1970)
Plummer, M.D.: On \(n\)-extendable graphs. Discrete Math. 31, 201–210 (1980)
Plummer, M.D.: Extending matchings in graphs: a survey. Discrete Math. 127(1–3), 277–292 (1994)
Poljak, S.: A note on stable sets and colorings in graphs. Comment. Math. Univ. Carol. 15, 307–309 (1974)
Ravindra, G.: B-graphs. In: Proceedings of the Symposium Graph Theory, ISI Lecture Notes Calcutta, 4, 268–280 (1976)
Ravindra, G.: Well covered graphs. J. Comb. Inform. Syst. Sci. 2, 20–21 (1977)
Sankaranarayana, R.S., Stewart, L.K.: Complexity results for well-covered graphs. Networks 22(3), 247–262 (1992)
Tankus, D., Tarsi, M.: Well-covered claw-free graphs. J. Comb. Theory Ser. B 66(2), 293–302 (1996)
The Network Simulator ns-3. https://www.nsnam.org/, 2022. Accessed on 30 Sept. 2021
Valiant, L.G.: Universality considerations in VLSI circuits. IEEE Trans. Comput. 30(2), 135–140 (1981)
Funding
Partially supported by the LABEX MILYON (ANR-10-LABX-0070) of Université de Lyon, within the program “Investissements d’Avenir” (ANR-11-IDEX-0007), and the research grant ANR DIGRAPHS ANR-19-CE48-0013-01, operated by the French National Research Agency (ANR).
Author information
Authors and Affiliations
Contributions
All authors participated equally to this work.
Corresponding author
Ethics declarations
Conflict of interest
The authors declare no competing interests.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Bergé, P., Busson, A., Feghali, C. et al. 1-Extendability of Independent Sets. Algorithmica 86, 757–781 (2024). https://doi.org/10.1007/s00453-023-01138-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00453-023-01138-8