{ "id": "2205.03965", "version": "v1", "published": "2022-05-08T22:48:00.000Z", "updated": "2022-05-08T22:48:00.000Z", "title": "Connected size Ramsey numbers of matchings versus a small path or cycle", "authors": [ "Sha Wang", "Ruyu Song", "Yixin Zhang", "Yanbo Zhang" ], "comment": "9 pages", "categories": [ "math.CO" ], "abstract": "Given two graphs $G_1, G_2$, the connected size Ramsey number ${\\hat{r}}_c(G_1,G_2)$ is defined to be the minimum number of edges of a connected graph $G$, such that for any red-blue edge colouring of $G$, there is either a red copy of $G_1$ or a blue copy of $G_2$. Concentrating on ${\\hat{r}}_c(nK_2,G_2)$ where $nK_2$ is a matching, we generalise and improve two previous results as follows. Vito, Nabila, Safitri, and Silaban obtained the exact values of ${\\hat{r}}_c(nK_2,P_3)$ for $n=2,3,4$. We determine its exact values for all positive integers $n$. Rahadjeng, Baskoro, and Assiyatun proved that ${\\hat{r}}_c(nK_2,C_4)\\le 5n-1$ for $n\\ge 4$. We improve the upper bound from $5n-1$ to $\\lfloor (9n-1)/2 \\rfloor$. In addition, we show a result which has the same flavour and has exact values: ${\\hat{r}}_c(nK_2,C_3)=4n-1$ for all positive integers $n$.", "revisions": [ { "version": "v1", "updated": "2022-05-08T22:48:00.000Z" } ], "analyses": { "keywords": [ "connected size ramsey number", "small path", "exact values", "positive integers", "blue copy" ], "note": { "typesetting": "TeX", "pages": 9, "language": "en", "license": "arXiv", "status": "editable" } } }