For two graphs $ G_1 $ and $ G_2 $, the connected size Ramsey number $ {\hat{r}}_c(G_1, G_2) $ is the smallest number of edges of a connected graph $ G $ such that if each edge of $ G $ is colored red or blue, then $ G $ contains either a red copy of $ G_1 $ or a blue copy of $ G_2 $. Let $ nK_2 $ be a matching with $ n $ edges and $ P_4 $ a path with four vertices. Rahadjeng, Baskoro, and Assiyatun [Procedia Comput. Sci. 74 (2015), 32-37] conjectured that $ \hat{r}_{c}(nK_2, P_4) = 3n-1 $ if $ n $ is even, and $ \hat{r}_{c}(nK_2, P_4) = 3n $ otherwise. We verify the conjecture in this short paper.
Citation: Yixin Zhang, Yanbo Zhang, Hexuan Zhi. A proof of a conjecture on matching-path connected size Ramsey number[J]. AIMS Mathematics, 2023, 8(4): 8027-8033. doi: 10.3934/math.2023406
For two graphs $ G_1 $ and $ G_2 $, the connected size Ramsey number $ {\hat{r}}_c(G_1, G_2) $ is the smallest number of edges of a connected graph $ G $ such that if each edge of $ G $ is colored red or blue, then $ G $ contains either a red copy of $ G_1 $ or a blue copy of $ G_2 $. Let $ nK_2 $ be a matching with $ n $ edges and $ P_4 $ a path with four vertices. Rahadjeng, Baskoro, and Assiyatun [Procedia Comput. Sci. 74 (2015), 32-37] conjectured that $ \hat{r}_{c}(nK_2, P_4) = 3n-1 $ if $ n $ is even, and $ \hat{r}_{c}(nK_2, P_4) = 3n $ otherwise. We verify the conjecture in this short paper.
[1] | H. Assiyatun, B. Rahadjeng, E. T. Baskoro, The connected size Ramsey number for matchings versus small disconnected graphs, Electron. J. Graph Theory Appl., 7 (2019), 113–119. http://dx.doi.org/10.5614/ejgta.2019.7.1.9 doi: 10.5614/ejgta.2019.7.1.9 |
[2] | J. Beck, On size Ramsey number of paths, trees, and circuits. Ⅰ, J. Graph Theory, 7 (1983), 115–129. https://doi.org/10.1002/jgt.3190070115 doi: 10.1002/jgt.3190070115 |
[3] | J. A. Bondy, U. S. R. Murty, Graph theory, Springer, 2008. https://doi.org/10.1007/978-1-84628-970-5 |
[4] | S. A. Burr, P. Erdős, R. J. Faudree, C. C. Rousseau, R. H. Schelp, Ramsey-minimal graphs for multiple copies, Indag. Math. (N.S.), 81 (1978), 187–195. https://doi.org/10.1016/1385-7258(78)90036-7 doi: 10.1016/1385-7258(78)90036-7 |
[5] | A. Davoodi, R. Javadi, A. Kamranian, G. Raeisi, On a conjecture of Erdős on size Ramsey number of star forests, arXiv: 2111.02065, 2021. Available from: https://arXiv.org/abs/2111.02065 |
[6] | Jr. D. Dellamonica, The size‐Ramsey number of trees, Random Struct. Algor., 40 (2012), 49–73. https://doi.org/10.1002/rsa.20363 doi: 10.1002/rsa.20363 |
[7] | A. Dudek, P. Prałat, On some multicolor Ramsey properties of random graphs, SIAM J. Discrete Math., 31 (2017), 2079–2092. https://doi.org/10.1137/16M1069717 doi: 10.1137/16M1069717 |
[8] | P. Erdős, R. J. Faudree, Size Ramsey numbers involving matchings, Finite and Infinite Sets, (1984), 247–264. https://doi.org/10.1016/B978-0-444-86893-0.50019-X doi: 10.1016/B978-0-444-86893-0.50019-X |
[9] | P. Erdős, R. J. Faudree, C. C Rousseau, R. H. Schelp, The size Ramsey number, Period. Math. Hungar., 9 (1978), 145–161. https://doi.org/10.1007/BF02018930 doi: 10.1007/BF02018930 |
[10] | R. J. Faudree, J. Sheehan, Size Ramsey numbers for small‐order graphs, J. Graph Theory, 7 (1983), 53–55. https://doi.org/10.1002/jgt.3190070107 doi: 10.1002/jgt.3190070107 |
[11] | R. J. Faudree, J. Sheehan, Size Ramsey numbers involving stars, Discrete Math., 46 (1983), 151–157. https://doi.org/10.1016/0012-365X(83)90248-0 doi: 10.1016/0012-365X(83)90248-0 |
[12] | F. Harary, Z. Miller, Generalized Ramsey theory Ⅷ, The size Ramsey number of small graphs, In Studies in Pure Mathematics, (1983), 271–283. https://doi.org/10.1007/978-3-0348-5438-2_25 |
[13] | P. E. Haxell, Y. Kohayakawa, The size-Ramsey number of trees, Israel J. Math., 89 (1995), 261–274. https://doi.org/10.1007/BF02808204 doi: 10.1007/BF02808204 |
[14] | P. E. Haxell, Y. Kohayakawa, T. Łuczak, The induced size-Ramsey number of cycles, Combin. Probab. Comput., 4 (1995), 217–239. https://doi.org/10.1017/S0963548300001619 doi: 10.1017/S0963548300001619 |
[15] | R. Javadi, F. Khoeini, G. R. Omidi, A. Pokrovskiy, On the size-Ramsey number of cycles, Combin. Probab. Comput., 28 (2019), 871–880. https://doi.org/10.1017/S0963548319000221 doi: 10.1017/S0963548319000221 |
[16] | R. Javadi, G. Omidi, On a question of Erdős and Faudree on the size Ramsey numbers, SIAM J. Discrete Math., 32 (2018), 2217–2228. https://doi.org/10.1137/17M1115022 doi: 10.1137/17M1115022 |
[17] | R. Lortz, I. Mengersen, Size Ramsey results for paths versus stars, Australas. J. Combin., 18 (1998), 3–12. |
[18] | R. Lortz, I. Mengersen, Size Ramsey results for the path of order three, Graphs Combin., 37 (2021), 2315–2331. https://doi.org/10.1007/s00373-021-02398-3 doi: 10.1007/s00373-021-02398-3 |
[19] | M. Miralaei, G. R. Omidi, M. Shahsiah, Size Ramsey numbers of stars versus cliques, J. Graph Theory, 92 (2019), 275–286. https://doi.org/10.1002/jgt.22453 doi: 10.1002/jgt.22453 |
[20] | B. Rahadjeng, E. T. Baskoro, H. Assiyatun, Connected size Ramsey numbers for matchings versus cycles or paths, Procedia Comput. Sci., 74 (2015), 32–37. https://doi.org/10.1016/j.procs.2015.12.071 doi: 10.1016/j.procs.2015.12.071 |
[21] | B. Rahadjeng, E. T. Baskoro, H. Assiyatun, Connected size Ramsey numbers of matchings and stars, AIP Conf. Proc., 1707 (2016), 020015. https://doi.org/10.1063/1.4940816 doi: 10.1063/1.4940816 |
[22] | B. Rahadjeng, E. T. Baskoro, H. Assiyatun, Connected size Ramsey number for matchings vs. small stars or cycles, Proc. Indian Acad. Sci.: Math. Sci., 127 (2017), 787–792. https://doi.org/10.1007/s12044-017-0366-z doi: 10.1007/s12044-017-0366-z |
[23] | J. Sheehan, R. J. Faudree, C. C. Rousseau, A class of size Ramsey problems involving stars, Graph Theory and Combinatorics, (1983), 273–281. |
[24] | V. Vito, A. C. Nabila, E. Safitri, D. R. Silaban, The size Ramsey and connected size Ramsey numbers for matchings versus paths, J. Phys. Conf. Ser., 1725 (2021), 012098. https://doi.org/10.1088/1742-6596/1725/1/012098 doi: 10.1088/1742-6596/1725/1/012098 |
[25] | V. Vito, D. R. Silaban, Two types of size Ramsey numbers for matchings of small order, J. Discrete Math. Sci. Cryptogr., (2022), 1–13. https://doi.org/10.1080/09720529.2021.2000153 doi: 10.1080/09720529.2021.2000153 |
[26] | S. Wang, R. Song, Y. Zhang, Y. Zhang, Connected size Ramsey numbers of matchings versus a small path or cycle, arXiv: 2205.03965, 2022. Available from: https://arXiv.org/abs/2205.03965 |