{ "id": "2101.00507", "version": "v1", "published": "2021-01-02T20:04:47.000Z", "updated": "2021-01-02T20:04:47.000Z", "title": "Minimizing the number of complete bipartite graphs in a $K_s$-saturated graph", "authors": [ "Beka Ergemlidze", "Abhishek Methuku", "Michael Tait", "Craig Timmons" ], "categories": [ "math.CO" ], "abstract": "A graph $G$ is $F$-saturated if it contains no copy of $F$ as a subgraph but the addition of any new edge to $G$ creates a copy of $F$. We prove that for $s \\geq 3$ and $t \\geq 2$, the minimum number of copies of $K_{1,t}$ in a $K_s$-saturated graph is $\\Theta ( n^{t/2})$. More precise results are obtained when $t = 2$ where the problem is related to Moore graphs with diameter 2 and girth 5. We prove that for $s \\geq 4$ and $t \\geq 3$, the minimum number of copies of $K_{2,t}$ in an $n$-vertex $K_s$-saturated graph is at least $\\Omega( n^{t/5 + 8/5})$ and at most $O(n^{t/2 + 3/2})$. These results answer a question of Chakraborti and Loh. General estimates on the number of copies of $K_{a,b}$ in a $K_s$-saturated graph are also obtained, but finding an asymptotic formula remains open.", "revisions": [ { "version": "v1", "updated": "2021-01-02T20:04:47.000Z" } ], "analyses": { "subjects": [ "05C35" ], "keywords": [ "saturated graph", "complete bipartite graphs", "asymptotic formula remains open", "minimum number", "moore graphs" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }